Unicast IPv4 Routing Tools and Settings
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
In this section
Unicast IPv4 Routing Tools
Unicast IPv4 Routing Registry Entries
Related Information
You can use the unicast IPv4 routing tools and registry settings described here to enable, configure, and manage the unicast IPv4 routing features provided by the Microsoft® Windows® Server™ 2003 Routing and Remote Access service.
Unicast IPv4 Routing Tools
The sets of tools listed in the following table are associated with unicast IPv4 routing as supported by the Windows Server 2003 Routing and Remote Access service.
Available Tools for Unicast IPv4 Routing
| Category | Tools in This Set |
|---|---|
Command-line tools used for unicast IPv4 routing |
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Graphical user interface tools used for unicast IPv4 routing |
|
Each of these tools is described in the following sections.
You can specify commands for the command-line tools for one or more remote servers by establishing a remote access connection to each server from a workstation running Microsoft Windows XP or from another server, and then opening a command prompt window in the remote access window for each server. You can also specify Network Connections and Routing and Remote Access snap-in options by establishing a remote access connection. In addition, you can use the Remote Access snap-in to manage multiple servers running the Routing and Remote Access service by accessing the node for each server.
Netsh.exe: Netsh Commands for Managing IPv4 Routing
Category The Netsh commands for IPv4 routing are a subset of the Netsh command-line tools that are included with the Windows Server 2003 operating system. In many cases, a Netsh command can be used to manage the Routing and Remote Access service as an alternative to using an option available in the Routing and Remote Access snap-in. Netsh also includes commands for IPv6.
Version compatibility The Netsh commands for IP routing are compatible with the Windows Server 2003 operating system. Netsh commands were first introduced in Microsoft Windows 2000 Server and were expanded to include additional commands in Windows Server 2003.
The Netsh commands help network administrators manage a TCP/IP network. You can use Netsh locally or remotely to display or modify the configuration of services or protocols on Windows-based computers. The Netsh command-line interface is scriptable, which lets you perform batch configurations or remote network administration from a single location.
Netsh provides sets of commands (also known as contexts) for performing a wide range of network configuration tasks. In addition to a few commands from the Netsh ras and Netsh interface contexts, this document describes several Netsh Routing IP contexts used in conjunction with the unicast IPv4 routing features of the Routing and Remote Access service.
For more information about Netsh, see Command-Line Reference for Windows Server 2003, Standard Edition. In particular, for information about IP routing-related commands not included in this technical reference, see the following Netsh contexts:
Netsh ras context, for remote access configuration.
Netsh interface context, for configuration of demand-dial interfaces.
Netsh routing IP NAT context, for network address translation (NAT).
Netsh interface IPv6 context, for manually configuring IPv6 settings.
Netsh routing IP IGMP context, for multicast routing.
Each of the listed Netsh contexts contains unicast routing–related commands not included in this technical reference, except for the IGMP context, which contains multicast routing–related commands.
How to access Netsh commands
You can access a particular command in any Netsh context in one of the following two ways:
Type the entire path for the command at the command prompt. For example, to view IPv4 router discovery configuration data, type the following command at a command prompt:
C:\>netsh routing ip routerdiscovery show interface name="Local Area Connection"
The preceding command produces the following output:
Router Discovery Information for Local Area Connection 3
----------------------------------------------------------------------
Router Discovery is: Disabled
Minimum Advertisement Interval: 7 minutes
Maximum Advertisement Interval: 10 minutes
Advertisement Lifetime: 30 minutes
Preference Level: 0
Access the context containing the command that you want to use, and then type only the specific command. The following series of commands displays the same output as the preceding example:
C:\>netsh
netsh>routing
netsh routing>ip
netsh routing ip>routerdiscovery
netsh routing ip routerdiscovery>show interface name="Local Area Connection"
The preceding series of commands produce the following output:
Router Discovery Information for Local Area Connection 3
----------------------------------------------------------------------
Router Discovery is: Disabled
Minimum Advertisement Interval: 7 minutes
Maximum Advertisement Interval: 10 minutes
Advertisement Lifetime: 30 minutes
Preference Level: 0
The following sections contain a brief description of unicast IPv4 routing commands that are related to the Routing and Remote Access service and that are available for the following Netsh contexts:
Netsh ras context (includes only commands for configuring file tracing)
Netsh routing IP context (includes only commands for configuring IP packet filtering, interfaces, persistent and non-persistent static routes, and preference levels for route sources)
Netsh routing IP OSPF context
Netsh routing IP relay context
Netsh routing IP RIP context
Netsh routing IP routerdiscovery context
Netsh ras context
The Routing and Remote Access service provides extensive tracing capability to help troubleshoot complex network problems. Separate routing components can be independently enabled so that tracing information can be logged to files (known as file tracing). Logged data includes information about internal component variables, function calls, and interactions. You can enable and disable tracing for routing protocols while the router is running.
Note
You can also enable file tracing for Routing and Remote Access components, such as the RIP and OSPF routing protocols, by editing the registry (see Unicast IPv4 Routing Registry Entries later in this document). However, using Netsh commands is the recommended method.
Tracing consumes system resources and must be used sparingly. After you obtain the trace or identify the problem, immediately disable tracing. In particular, do not leave tracing enabled on multiprocessor computers.
The Netsh ras context includes primarily remote access–related commands, which are not included here. The following table lists only the file tracing commands for the RIP v2 and OSPF routing protocols that are available in the Netsh ras context.
Unicast IPv4 Routing Commands in the Netsh Ras Context
| Command | Task |
|---|---|
Set |
You can use the following commands:
|
Show |
You can use the following commands:
|
Most of the commands available in the Netsh ras context are used for remote access networking, such as for demand-dial or virtual private network (VPN) connections. These commands are also unicast IPv4 commands, but they are not covered in this technical reference. For more information about tools for remote access networking, see Demand Dial Tools and Settings and VPN Tools and Settings.
Netsh routing IP context
The partial set of commands included in this document for this context are the Netsh commands used to configure IP packet filtering, which can help increase security on a private IP internetwork connected to the Internet by specifying which IP packet traffic is accepted or rejected; the commands used to configure interfaces, persistent and non-persistent static routes; and preference levels for route sources. Also included, in separate sections later in this document, are several relevant contexts accessible under the Netsh routing IP context: the OSPF, RIP, relay (for the DHCP relay agent), and IP router discovery contexts.
Excluded from this technical reference are Netsh commands used for IPv4 multicast routing, network address translation (NAT), DHCP, DNS, and remote access.
The following table describes commands available in the Netsh routing IP context that are relevant to the unicast IPv4 routing services provided by the Routing and Remote Access service.
Unicast IPv4 Routing Commands in the Netsh Routing IP Context
| Command | Task | ||
|---|---|---|---|
Add |
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Delete |
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Dump |
Creates a script that contains the current configuration for this server. If you save the script to a file, you can use it to restore altered configuration settings or to configure a new server. “Current configuration” refers to all configuration settings in and below the specific node in the Routing and Remote Access snap-in at which the command “dump” is given. Because this table refers to the Netsh routing IP context, in this case, the dump command includes all configuration settings in the IP Routing node and any configured child nodes, including the General, Static Routes, DHCP Relay Agent, OSPF, NAT/Basic Firewall, and IGMP nodes. If you plan to make extensive changes to the configuration of this server, a recommended practice is to begin the configuration session by using the dump command before you start, in case you need to restore the configuration later. |
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Set |
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Show |
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Note1. The Routing and Remote Access service on a router running Windows Server 2003 maintains the IP routing table by using a component called the Route Table Manager, abbreviated as “rtm” in the commands rtmroutes and rtmdestinations. The Route Table Manager updates the IP forwarding table based on incoming route information from multiple sources.
Netsh routing IP OSPF context
Open Shortest Path First (OSPF), the most common routing protocol used on large and very large IPv4 internetworks, enables the dynamic exchange of IPv4 routing information between OSPF routers across complex internetworks. Typically, OSPF is deployed on private IP internetworks connected to the public Internet, including internetworks that span multiple geographical regions, nations, or continents.
OSPF is structured as an autonomous system made up of one or more OSPF areas. Each area is made up of a logical collection of networks, routers, and links, and each area includes special OSPF routers that enable communication among the constituent areas. OSPF routers in each area dynamically build and synchronize a database of the OSPF network topology, called a link state database (LSDB). The LSDB is a topological map of all routers in the same OSPF area, and OSPF routers can update the LSDB in response to topology changes.
The following table describes the commands available in the Netsh routing IP OSPF context. The OSPF routing protocol is provided by the Windows Server 2003 Routing and Remote Access service.
Commands in the Netsh Routing IP OSPF Context
| Command | Task |
|---|---|
Add |
|
Delete |
|
Dump |
Creates a script that contains the current configuration for OSPF. If you save the script to a file, you can use it to restore altered configuration settings or to configure a new OSPF router. If you plan to make extensive changes to the configuration of an OSPF router, a recommended practice is to begin the configuration session by using the dump command before you start, in case you need to restore the configuration later. |
Install |
Installs the OSPF routing protocol under the IP routable protocol. |
Set |
|
Show |
|
Uninstall |
Removes the OSPF routing protocol. |
Netsh routing IP relay context
Any IPv4 subnet that contains DHCP clients requires either a DHCP server or a properly configured DHCP relay agent to provide address leases to those DHCP clients. A computer acting as a DHCP relay agent forwards DHCP messages between DHCP clients on an IP subnet that has no DHCP server and a DHCP server located on a different subnet. Using DHCP relay agents make it unnecessary to install a separate DHCP server on each subnet.
The following table describes the commands related to DHCP and DHCP relay agent in the Netsh routing IP relay context. The capability to enable a router to act as a DHCP relay agent is provided by the Windows Server 2003 Routing and Remote Access service.
Commands in the Netsh Routing IP Relay Context
| Command | Task |
|---|---|
Add |
|
Delete |
|
Dump |
Creates a script that contains the current configuration for the DHCP relay agent. If you save the script to a file, you can use it to restore altered configuration information. If you plan to make extensive changes to the configuration of a DHCP relay agent, a recommended practice is to begin the configuration session by using the dump command before you start, in case you need to restore the configuration later. |
Install |
Installs the DHCP Relay Agent service. |
Set |
|
Show |
|
Uninstall |
Removes the DHCP Relay Agent service. |
Netsh routing IP RIP context
Routing Information Protocol (RIP), the primary dynamic routing protocol used on small or medium-sized IPv4 internetworks (10 to 50 networks), enables the dynamic exchange of IPv4 routing information between RIP routers. RIP routers can update IP internetwork topology changes as networks are added or removed and as links fail and are restored.
The following table describes the commands available in the Netsh routing IP RIP context. The RIP routing protocol is provided by the Windows Server 2003 Routing and Remote Access service, which supports both the updated version of RIP, RIP version 2 (RIP v2) and the earlier version of RIP, RIP version 1 (RIP v1).
Commands Available in the Netsh Routing IP RIP Context
| Command | Task |
|---|---|
Add |
|
Delete |
|
Dump |
Creates a script that contains the current configuration for RIP. If you save the script to a file, you can use it to restore altered configuration information or to configure a new RIP router. If you plan to make extensive changes to the configuration of a RIP router, a recommended practice is to begin the configuration session by using the dump command before you start, in case you need to restore the configuration later. |
Install |
Installs the RIP routing protocol under the IP routable protocol. |
Set |
|
Show |
|
Uninstall |
Removes the RIP routing protocol |
Netsh routing IP routerdiscovery context
In unicast IPv4 routing, ICMP router discovery is an alternative to using manually configured or DHCP-configured default gateways.
Note
In IPv6 unicast routing, IPv6 Neighbor Discovery (ND) replaces and improves the functionality of Address Resolution Protocol (ARP), ICMP Router Discovery, and ICMP Redirect, which together are the IPv4 counterparts for IPv6 ND. ND, which is a set of messages and processes that determine relationships between neighboring nodes, is described in RFC 2461, "Neighbor Discovery for IP Version 6 (IPv6)," in the IETF RFC Database.
ICMP router discovery automates the discovery and configuration of the default gateway so that IP hosts can dynamically discover the best default gateway to use on a subnet and can automatically switch to another default gateway if the first default gateway fails or if the network administrator changes router preferences.
The following table describes the commands for ICMP router discovery in the Netsh routing IP routerdiscovery context. ICMP router discovery is provided by the Windows Server 2003 Routing and Remote Access service.
Commands in the Netsh Routing IP Routerdiscovery Context
| Command | Task |
|---|---|
Add |
Add interface. On the specified interface, specifies the following:
|
Delete |
Delete interface. Disables ICMP router discovery configuration for the specified interface. |
Dump |
Creates a script that contains the current configuration of the ICMP router discovery component. If you save the script to a file, you can use it to restore altered configuration information. If you plan to make extensive changes to the configuration of the ICMP router discovery component, a recommended practice is to begin the configuration session by using the dump command before you start, in case you need to restore the configuration later |
Set |
Set interface. On the specified interface, updates the following:
|
Show |
Show interface. For the specified interface, displays:
|
Uninstall |
Removes ICMP router discovery from all interfaces on this server. If, later, you want to reenable ICMP router discovery by using the add interface command, you must add ICMP router discovery one interface at a time. |
Management and Diagnostic Command-Line Tools for Unicast IPv4 Routing
In addition to the Netsh command-line tool, Windows Server 2003 also supports the Pathping, Ping, Route, and Tracert command-line tools for unicast IPv4 and IPv6 network traffic. This section describes each tool as used for unicast IPv4 routing–related tasks in an IPv4 internetworking environment. For information about these tools in an IPv6 internetworking environment, see IPv6 Tools and Settings.
Pathping.exe
Category The Pathping.exe diagnostic tool for IPv4 internetworks is included with the Windows Server 2003 operating system. The Windows Server 2003 version of Pathping.exe also supports IPv6.
Version compatibility The Pathping.exe tool runs on Windows Server 2003, Windows XP, and Windows 2000.
Pathping combines information provided by Tracert (identifying which routers exist along the path) and Ping (repeatedly sending messages to each router) with additional information that neither of those tools provides.
The Pathping tool uses ICMP Echo messages to test router latency, link latency, and packet losses on an IPv4 internetwork. Pathping tests each hop by pinging multiple times over a period of time, and then displaying delay and packet loss information per hop. Specifically, Pathping records the following:
The average round-trip time.
The packet loss when sending ICMP Echo messages to each router.
The packet loss when sending ICMP Echo messages across the links between each router.
The output of the Pathping command can help you determine if there is a high-loss link or router in the path by showing the degree of packet loss at each router or link.
For more information about Pathping.exe, see Command-Line Reference for Windows Server 2003, Standard Edition.
Ping.exe
Category The Ping.exe diagnostic tool for IPv4 internetworks is included with the Windows Server 2003 operating system. The Windows Server 2003 version of Ping.exe also supports IPv6.
Version compatibility The Ping.exe tool runs on Windows Server 2003, Windows XP, Windows 2000, and Windows NT® 4.0.
The Ping tool tests reachability on an IPv4 internetwork by sending an ICMP Echo message from a source host to a destination IP address and recording the results. Ping indicates whether the destination responds by displaying an ICMP Echo Response message and how much time elapses (in milliseconds) before a reply is received. If Ping receives no response, it displays an error message instead.
In addition to testing connectivity to a destination computer, successfully pinging from the local computer by IP address, not by name, verifies that TCP/IP is functioning properly on the local computer. Likewise, successfully pinging the local router verifies that the router is functioning.
For more information about Ping.exe, see Command-Line Reference for Windows Server 2003, Standard Edition.
Route.exe
Category The Route.exe management tool for IPv4 internetworks is included with the Windows Server 2003 operating system. The Windows Server 2003 version of Route.exe also supports IPv6.
Version compatibility The Route.exe tool runs on Windows Server 2003, Windows XP, Windows 2000, and Windows NT 4.0.
The Route tool displays and modifies entries in the IPv4 routing table on the local computer. You can use Route to add a temporary or persistent route, to change an existing route, or to remove a route from the IP routing table. The Route tool has four subcommands, listed in the following table.
Subcommands for Route.exe
| Subcommand | Task |
|---|---|
Route print |
Prints the IPv4 routing table and (if IPv6 exists) the IPv6 routing table. You can also use route print to display only part of the routing table. For example, if you use route print to display the entire routing table and then decide that you want to look only at the set of routes that begin with, say, 157, you can use route print 157* to print only those routes that match 157*. |
Route add |
Adds a static route. In Windows Server 2003, this subcommand does not support IPv6. |
Route delete |
Deletes a static route. In Windows Server 2003, this subcommand does not support IPv6. |
Route change |
Modifies an existing static route. This command is used only to modify gateway or metric values. In Windows Server 2003, this subcommand does not support IPv6 |
The IP routing table is stored in RAM, which means that a non-persistent static route disappears whenever a computer restarts. Typically, therefore, you use route add with the -p option to add a persistent static route that continues to exist even after a computer restarts.
Persistent routes are stored in the registry in the PersistentRoutes entry under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters. Because you can add, modify, or delete a persistent static route by using the Route tool, you do not need to configure this registry entry directly.
For more information about Route.exe, see Command-Line Reference for Windows Server 2003, Standard Edition.
Tracert.exe
Category The Tracert.exe diagnostic tool for IPv4 internetworks is included with the Windows Server 2003 operating system. The Windows Server 2003 version of Tracert.exe also supports IPv6.
Version compatibility The Tracert.exe tool runs on Windows Server 2003, Windows XP, Windows 2000, and Windows NT 4.0.
The Tracert route tracking tool tests reachability, network latency, routing loops, and other issues on an IPv4 internetwork by determining the path (the series of routers) that unicast IPv4 traffic takes between a source host and destination IP address. Tracert sends ICMP Echo messages with incrementally higher values of the Time to Live (TTL) field in the IP header and then returns (lists) the series of near-side router interfaces on each router between the source and destination hosts. If the intended destination host does not receive the packets sent, Tracert displays the last router that successfully forwarded the packets.
For more information about Tracert.exe, see Command-Line Reference for Windows Server 2003, Standard Edition.
Network Connections
For unicast IPv4 routing, Network Connections is used to configure default gateway options and other options for TCP/IP.
Category Network Connections is included with the Windows Server 2003 operating system.
Version compatibility Network Connections runs on Windows Server 2003 and Windows XP. Network Connections is known as Network and Dial-up Connection in Windows 2000. Network Connections is known as the Network component of Control Panel in Windows NT 4.0.
The Network Connections management tool enables the configuration of TCP/IP properties for a variety of purposes. The following table describes only the options used for manually configuring the default gateway and the related automatic metric option.
TCP/IP Properties Options in Network Connections
| Page | Tab | Task |
|---|---|---|
TCP/IP Properties |
General |
Manually configuring a network adapter to point to a default gateway:
|
Advanced TCP/IP Settings |
IP Settings |
Adding, editing, or removing additional default gateways for this network connection:
Enabling the option to automatically calculate the interface cost based on the speed of the interface:
Disabling the option to automatically calculate the interface cost based on the speed of the interface:
|
For related information about tools for configuring IP routers and hosts to enable hosts to dynamically discover the best default gateway to use on a subnet, see “Netsh routing IP routerdiscovery context” earlier in this document and see “ICMP router discovery options” later in this document.
Rrasmgmt.msc: Routing and Remote Access Snap-in
For unicast IPv4 routing, the Routing and Remote Access snap-in is used to configure options for a variety of functions provided by the Routing and Remote Access service. These functions include event logging, route source preference levels, the RIP for IP and OSPF routing protocols, the DHCP relay agent, IP packet filtering, and ICMP router discovery.
Category The Routing and Remote Access snap-in of Microsoft Management Console (MMC) is included with Windows Server 2003 operating system. Routing and Remote Access is disabled by default.
Version compatibility The Routing and Remote Access snap-in is provided by the Routing and Remote Access service on computers running Windows Server 2003 and Windows 2000 Server. For Windows NT 4.0, the Routing and Remote Access Service (RRAS) and its snap-in are available as a separate download from the Microsoft Windows NT Server Routing and Remote Access Service Download page.
You can use the Routing and Remote Access snap-in to enable, configure, or modify, unicast IPv4 routing options for RIP, OSPF, DHCP relay agent, IP packet filtering, and ICMP router discovery. The Routing and Remote Access snap-in can also be used to configure options for a variety of other routing or remote access services unrelated to these unicast IPv4 routing topics, such as configuring remote access connections, multicast IPv4 routing options, or network address translation (NAT).
Options for enabling, disabling, or refreshing the Routing and Remote Access service
The Routing and Remote Access snap-in is available by default in Administrative Tools in Control Panel. However, the Routing and Remote Access service managed by means of this snap-in is disabled by default.
Note
You do not use the Add or Remove Programs icon in Control Panel to install or uninstall the Routing and Remote Access service.
The following table describes the options to enable, disable, or refresh the Windows Server 2003 Routing and Remote Access service. These settings are available in the console tree of the Routing and Remote Access snap-in by right-clicking the ServerName node.
Options to Enable, Disable, or Refresh the Routing and Remote Access Service
| Node | Task | ||
|---|---|---|---|
ServerName |
Enabling the Routing and Remote Access service:
Disabling the Routing and Remote Access service:
Refreshing the Routing and Remote Access service:
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General options
Options available in the IP Routing\General container in the Routing and Remote Access snap-in take effect at the level of the server rather than at the level of an individual component of the Routing and Remote Access service. General options include those for setting global logging levels and for ranking route sources. You can also set logging levels at the level of the individual component.
This section includes unicast IPv4 routing options available in the console tree on the IP Routing\General node of the Routing and Remote Access snap-in and in the details pane on the InterfaceName Properties page. Multicast routing options are not included in this section. For more information, see IPv4 Multicasting Tools and Settings.
General options in the console tree
The following table describes the options for adding a new unicast IPv4 routing protocol to the Routing and Remote Access snap-in console tree and for adding an interface to the details pane. These options are available by right-clicking the IP Routing\General node.
Options on the IP Routing\General Node in the Console Tree
| Node | Task |
|---|---|
General |
Adding a new routing protocol to the console tree:
Adding a new interface to the details pane:
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The following table describes Routing and Remote Access options for configuring global IP logging and for ranking route source preference levels. These settings are available in the console tree of the Routing and Remote Access snap-in on the properties page of the IP Routing\General node. The properties page on the General node also includes a tab for Multicast Scopes, which is not covered in this technical reference.
Options on the IP Routing\General Properties Page
| Tab | Task | ||
|---|---|---|---|
Logging |
Configuring events to be logged in the System Log in Event Viewer for this server:
|
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Preference Levels |
Configuring the rank of route sources in order of preference by moving one or more of the listed route sources up or down (route sources are listed here in default order):
Note If two routes exist to the same destination, the route learned by the route source with a higher preference is preferred regardless of the route metric. For example, if the preference level for OSPF is higher than the preference level for RIP v2, an OSPF route with a metric of 5 is entered into the routing table rather than the same route discovered by RIP with a metric of 3. |
General options on the InterfaceName Properties page
For a description of unicast IPv4 routing configuration options available on the General tab of the InterfaceName Properties page in the IP Routing\General container, see the separate sections for “IP Packet Filtering Options” and “ICMP router discovery options” later in this document.
This InterfaceName Properties page also provides the Configuration tab to specify whether the IP address for this interface is statically configured or obtained dynamically from a DHCP server, and it provides the Multicast Boundaries and Multicast Heartbeat tabs to configure options related to IPv4 multicast routing. None of these options is described here because they are outside the scope of this technical reference.
RIP Options
Routing Information Protocol (RIP), the primary dynamic routing protocol used on small or medium-sized IPv4 internetworks (10 to 50 networks), enables the dynamic exchange of IPv4 routing information between RIP routers. By adding RIP to the Routing and Remote Access snap-in console tree, adding RIP interfaces to the details pane, and then configuring RIP options, you can enable RIP routers to update topology changes as networks are added or removed and as links fail and are restored.
The Windows Server 2003 Routing and Remote Access service supports both the updated version of RIP, RIP version 2 (RIP v2) and the earlier version of RIP, RIP version 1 (RIP v1). The version of RIP installed when you add the RIP protocol to the Routing and Remote Access snap-in console tree is RIP v2, which includes options that make RIP v1 optionally available.
This section includes unicast IPv4 routing options available in the console tree of the Routing and Remote Access snap-in on the IP Routing\RIP node and in the details pane on the InterfaceName Properties page.
RIP options in the console tree
The following table describes options for adding one or more interfaces to the details pane and for displaying information about neighboring RIP routers. These options are available by right-clicking the IP Routing\RIP node.
Options on the IP Routing\RIP Node in the Console Tree
| Node | Task |
|---|---|
RIP |
Adding a new interface to the details pane:
Displaying neighboring RIP routers:
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The following table describes Routing and Remote Access options for the RIP routing protocol. These settings are available in console tree of the Routing and Remote Access snap-in on properties page of the IP Routing\RIP node.
Options on the RIP Properties Page
| Tab | Task | ||
|---|---|---|---|
General |
Configuring the delay before this RIP router sends triggered updates:
Configuring events to be logged in the System Log in Event Viewer for this RIP router:
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Security |
Configuring the RIP routers from which this RIP router accepts announcements:
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RIP for IP options on the InterfaceName Properties page
The following table describes Routing and Remote Access options for a RIP interface. These settings are available in the Routing and Remote Access snap-in on the specified tab of the InterfaceName Properties page for an interface in the IP Routing\RIP container.
RIP Options on the InterfaceName Properties Page
| Tab | Task |
|---|---|
General |
Configuring Operation mode options for this interface:
Configuring Outgoing packet protocol options for sending outgoing RIP route announcements over this interface:
Configuring Incoming packet protocol options for receiving incoming RIP announcements over this interface:
Configuring metric and route tag options for this interface:
Configuring the simple password authentication option for this interface:
|
Security |
Configuring RIP security options for incoming routes on this interface:
Configuring RIP security options for outgoing routes on this interface:
|
Neighbors |
Configuring how this RIP router interacts with neighboring RIP routers through this interface:
|
Advanced |
Configuring RIP announcement and route interval options for this interface:
Configuring split-horizon processing and triggered updates options for this interface:
Configuring host and default route options for this interface:
Configuring subnet summarization option for this interface:
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OSPF options
Open Shortest Path First (OSPF), the most common routing protocol used on large and very large IPv4 internetworks, enables the dynamic exchange of IPv4 routing information between OSPF routers across complex internetworks. Adding OSPF to the Routing and Remote Access snap-in console tree, adding OSPF interfaces to the details pane, and then configuring OSPF options enables OSPF routers to update topology changes as networks are added or removed and as links fail and are restored.
This section includes unicast IPv4 routing options available in the console tree of the Routing and Remote Access snap-in on the IP Routing\OSPF node and in the details pane on the InterfaceName Properties page.
OSPF options in the console tree
The following table describes options for adding one or more interfaces to the details pane and for displaying information about the OSPF autonomous system. These options are available by right-clicking the IP Routing\OSPF node.
Options on the IP Routing\OSPF Node in the Console Tree
| Node | Task |
|---|---|
OSPF |
Adding a new interface to the details pane:
Displaying information about the OSPF autonomous system:
|
The following table describes Routing and Remote Access options for OSPF properties. These settings are available in the console tree of the Routing and Remote Access snap-in on the properties page of the IP Routing\OSPF node.
Options on the OSPF Properties Page
| Tab | Task | ||
|---|---|---|---|
General |
Configuring the OSPF router ID:
Configuring this OSPF router as an autonomous system boundary router (ASBR):
Configuring events to be logged in System Log in Event Viewer for this OSPF router:
|
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Areas |
Configuring OSPF areas (each OSPF interface on this OSPF router must belong to at least one OSPF area):
|
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Virtual Interfaces |
Configuring a virtual interface for this OSPF router: Note A virtual interface, also called a virtual link, is a logical connection that enables the exchange of routing information between a backbone area border router (ABR) and an ABR that is not physically connected to the backbone area. You cannot configure a virtual link across the backbone area or a stub area.
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External Routing |
Configuring external route source options:
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OSPF options on the InterfaceName Properties page
The following table describes Routing and Remote Access options for an OSPF interface. These settings are available in the Windows Server 2003 Routing and Remote Access snap-in on the specified tab of the InterfaceName Properties page for an interface in the IP Routing\OSPF container.
OSPF Options on the InterfaceName Properties Page
| Tab | Task |
|---|---|
General |
Configuring OSPF on this interface:
Configuring the network type on this interface by selecting one of the following:
|
NBMA Neighbors |
Configuring NBMA neighbors (available if Non-broadcast multiple access (NBMA) is selected as the network type on this interface’s General tab) for this interface:
|
Advanced |
Configuring advanced OSPF options for this interface:
|
DHCP Relay Agent options
Any IPv4 subnet that contains DHCP clients requires either a DHCP server or a DHCP relay agent to provide address leases to those DHCP clients. A computer acting as a DHCP relay agent, also known as a Bootstrap Protocol (BOOTP) relay agent, relays DHCP messages between DHCP clients on an IP subnet that has no DHCP server and a DHCP server located on a different subnet. By adding the DHCP relay agent to the Routing and Remote Access snap-in console tree, adding one or more DHCP relay agent interfaces to the details pane, and then configuring DHCP relay agent options, you can enable a router to act as a DCHP relay agent. Installation of a DHCP relay agent makes it unnecessary to install a separate DHCP server on each subnet in an IP internetwork.
This section includes unicast IPv4 routing options available in the console tree in the Routing and Remote Access snap-in on the IP Routing\DHCP Relay Agent node and in the details pane on the InterfaceName Properties page.
DHCP relay agent options in the console tree
The following table describes the option for adding one or more interfaces to the details pane. This option is available by right-clicking the IP Routing\DHCP Relay Agent node.
Options on the IP Routing\DHCP Relay Agent Node in the Console Tree
| Node | Task |
|---|---|
DHCP Relay Agent |
Adding a new interface to the details pane:
|
The following table describes Routing and Remote Access options for DHCP relay agent properties. These settings are available in the console tree of the Routing and Remote Access snap-in on the properties page of the IP Routing\DHCP Relay Agent node.
Options on the DHCP Relay Agent Properties Page
| Tab | Task |
|---|---|
General |
Configuring one or more DHCP servers for local clients to contact through the DHCP relay agent:
|
DHCP relay agent options on the InterfaceName Properties page
The following table describes Routing and Remote Access options for a DHCP relay agent interface. These settings are available in the Windows Server 2003 Routing and Remote Access snap-in on the General tab of the InterfaceName Properties page for an interface in the IP Routing\DHCP Relay Agent container.
DHCP Relay Agent Options on the InterfaceName Properties Page
| Tab | Task |
|---|---|
General |
Configuring a DHCP relay agent interface over which to route packets exchanged between DHCP clients on the local subnet and a DHCP server on another subnet:
|
IP packet filtering options
Configuring IP packet filters on an IP router helps increase security on a private IP internetwork that connects to a public network such as the Internet. When IP packet filtering is configured, a packet arriving at a router might be forwarded to its destination, rejected with an error message returned to notify the sender, or dropped with no error message sent.
The following table describes options for IP packet filtering available in the Windows Server 2003 Routing and Remote Access snap-in by selecting Inbound Filters or Outbound Filters on the General tab of the InterfaceName Properties page for an interface in the IP Routing\General container, and then selecting New or Edit. Note that, although the options for adding an inbound or an outbound filter shown in the table appear together in the same dialog box, typically filters are configured in pairs, either {Destination Network/Protocol}, or {Source Network/Protocol}. After you add a filter, you select one of the following filter actions:
Receive all packets except those that meet the criteria below.
Drop all packets except those that meet the criteria below.
If you configure multiple parameters on a particular filter, when the filter is applied to an incoming packet, the parameters of the filter are compared by using a logical AND operator. The fields in the packet must match all of the criteria of the filter to have the filter action applied.
IP Packet Filtering Options on the InterfaceName Properties Page
| Tab | Task | ||
|---|---|---|---|
General |
Adding inbound filters or outbound filters (in the Add IP Filter or Edit IP Filter dialog box):
Configuring fragmentation checking:
|
For examples of filter configurations for commonly implemented IP filtering scenarios on a Routing and Remote Access router, see “Filtering Scenarios” in How Unicast IPv4 Routing Protocols and Services Work.
ICMP router discovery options
Configuring ICMP router discovery, an alternative to using manually configured or DHCP-configured default gateways, provides an improved method of configuring and detecting the default gateway. For IP hosts, the default gateway is the IP router on the local subnet that forwards traffic to destinations that are not located on the local subnet.
The ICMP router discovery feature automates the discovery and configuration of the default gateway so that IP hosts can dynamically discover the best default gateway to use on a subnet and can automatically switch to another default gateway if the first default gateway fails or if the network administrator changes router preferences.
The following table describes Routing and Remote Access options for configuring ICMP router discovery on an IP router. These settings are available in the Windows Server 2003 Routing and Remote Access snap-in on the General tab of the InterfaceName Properties page for an interface in the IP Routing\General container.
ICMP Router Discovery Options on the InterfaceName Properties Page
| Tab | Task |
|---|---|
General |
Configuring options for ICMP router discovery on this interface:
|
In addition to enabling ICMP router discovery on the IP router, you must also configure router discovery on IP client computers on that router’s subnet:
For information about the tool used to configure ICMP router discovery on a client running Windows XP Professional, see “Netsh routing IP routerdiscovery context” in the section “Command-Line Tools for Unicast IPv4 Routing” earlier in this document.
For information about the tool used to configure ICMP router discovery on a client running Windows 2000 Professional, see “PerformRouterDiscovery” and “SolicitationAddressBcast” in the section Unicast IPv4 Routing Registry Entries later in this document.
Unicast IPv4 Routing Registry Entries
When the Routing and Remote Access service is enabled, it creates and maintains its settings in the Windows Server 2003 registry. For performance reasons, most Routing and Remote Access service configuration information is stored in binary format in large configuration blocks, not as separate registry entries that you can easily view or modify by using the Registry Editor (Regedit.exe) tool. This section includes only unicast IPv4 routing-related Routing and Remote Access registry entries that are configurable.
For more information about these and other registry entries, see the Windows Server 2003 Resource Kit Registry Reference.
The information here is provided as a reference for use in troubleshooting or verifying that the required settings are applied. It is recommended that you do not directly edit the registry unless there is no other alternative. Modifications to the registry are not validated by the registry editor or by Windows before they are applied, and as a result, incorrect values can be stored. This can result in unrecoverable errors in the system. When possible, use Group Policy or other Windows tools, such as Microsoft Management Console (MMC), to change configuration settings rather than editing the registry directly. If you must edit the registry, use extreme caution.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
The Routing and Remote Access service provides an extensive tracing capability to help troubleshoot complex network problems. Separate routing components can be independently enabled to log tracing information to files — this capability is called file tracing. File tracing includes information about internal component variables, function calls, and interactions. You can enable and disable tracing for routing protocols while the router is running. This section includes only file tracing registry keys for the RIP v2 and OSPF routing protocols.
The following registry keys are located under the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing.
IPRIP2
Registry path HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
Version Windows Server 2003 and Windows 2000 Server
Configuring entries under the IPRIP2 key enables file tracing, which logs tracing information about the RIP v2 routing protocol to files so that you can troubleshoot problems on a RIP internetwork.
Warning
The recommended method for enabling file tracing for RIP is to use the Netsh tool rather than by changing the registry settings shown here. For more information, see “Netsh ras context” earlier in this document.
Tracing consumes system resources and must be used sparingly. After you obtain the trace or identify the problem, immediately disable tracing. In particular, do not leave tracing enabled on multiprocessor computers.
The following table lists the registry entries for configuring file tracing for RIP v2.
Entries for Enabling Tracing Under the IPRIP2 Registry Key
| Entry | Task |
|---|---|
EnableFileTracing |
Configuring file tracing:
|
FileDirectory |
Configuring location of the file tracing log file:
|
FileTracingMask |
Configuring how much tracing information is saved in the log file:
|
MaxFileSize |
Configuring maximum log file size:
|
OSPF
Registry path HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
Version Windows Server 2003 and Windows 2000 Server
Configuring entries under the OSPF key enables file tracing, which logs tracing information about the OSPF routing protocol to files so that you can troubleshoot problems on an OSPF internetwork.
Warning
The recommended method for enabling file tracing for OSPF is to use the Netsh tool rather than by changing the registry settings shown here. For more information, see “Netsh ras context” earlier in this document.
Tracing consumes system resources and must be used sparingly. After you obtain the trace or identify the problem, immediately disable tracing. In particular, do not leave tracing enabled on multiprocessor computers.
The following table lists the registry entries for configuring file tracing for OSPF.
Entries for Enabling Tracing Under the OSPF Registry Key
| Entry | Task |
|---|---|
EnableFileTracing |
Configuring file tracing:
|
FileDirectory |
Configuring location of the file tracing log file:
|
FileTracingMask |
Configuring how much tracing information is saved in the log file:
|
MaxFileSize |
Configuring maximum log file size:
|
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Tcpip\Parameters
The Routing and Remote Access service uses several TCP/IP registry keys. The entries included in this section are those that are specific to unicast IPv4 routing. For additional entries for TCP/IP, see TCP/IP Tools and Settings.
The following registry entries are located under the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters.
DisableIPSourceRouting
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version Windows Server 2003, Windows XP, Windows 2000, Windows NT 4.0, or Windows 98
This entry determines whether IP source routing is enabled. IP source routing lets the sender use a tool, such as Tracert.exe or Ping.exe, to specify the exact route that an IP packet takes through successive IP routers across the IP internetwork.
Source routing is not typically implemented on IP internetworks. Instead, IP routing is typically handled through routing decisions made by source hosts and IP routers based on entries in their respective local routing tables. Although you might want to use IP source routing in network testing and debugging situations, disable IP source routing as soon as you are finished testing or troubleshooting.
Values for DisableIPSourceRouting
| Value | Setting |
|---|---|
0 |
Forwards all packets. |
1 (Default) |
Does not forward source routed packets. |
2 |
Drops all incoming source routed packets. |
EnableDeadGWDetect
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version Windows Server 2003, Windows XP, Windows 2000, Windows NT 4.0, or Windows 98
This entry determines whether dead gateway detection is enabled. With EnableDeadGWDetect enabled, TCP can detect a failure of the default gateway and inform IP to switch to a different default gateway if one is available. A default gateway is an IP router on the local subnet that can forward traffic to destinations located beyond the local subnet.
For optimal security, setting EnableDeadGWDetect to 0 is recommended in order to prevent an attacker from forcing this computer to switch to an unintended default gateway.
Values for EnableDeadGWDetect
| Value | Setting |
|---|---|
0 |
Disables dead gateway detection. |
1 (default) |
Enables dead gateway detection. |
EnableFastRouteLookup
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version Windows Server 2003, Windows 2000 Server
This entry, which is created only if the Routing and Remote Access Service is enabled, determines whether the fast route lookup feature is enabled. Fast route lookups make route searches faster but use a significant amount of non-paged pool memory. Fast route lookups are used only if the computer runs Windows Server 2003 or Windows 2000 Server and contains at least 64 MB of memory.
Values for EnableFastRouteLookup
| Value | Setting |
|---|---|
0 (default) |
Disables fast route lookup. |
1 |
Enables fast route lookup. |
EnableICMPRedirects
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version Windows Server 2003, Windows XP, Windows 2000
This entry determines whether a computer running Windows Server 2003 TCP/IP, or another version of Windows TCP/IP that supports Internet Control Message Protocol (ICMP) Redirect messages, updates its routing table in response to ICMP Redirect messages sent to it by a network device such as a router. An ICMP Redirect message instructs the computer to direct IP packets for the recipient along a different route. A computer running Windows Server 2003 accepts ICMP redirection messages from any node in the route between it and the destination computer.
You must restart the computer for changes to this entry to take effect.
Values for EnableICMPRedirects
| Value | Setting |
|---|---|
0 |
Disables updates of the IP routing table in response to ICMP Redirect messages. |
1 (default) |
Enables updates of the IP routing table in response to ICMP Redirect messages. |
EnablePMTUBHDetect
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version Windows Server 2003, Windows XP, Windows 2000
This entry determines whether TCP tries to detect black hole routers during the path maximum transmission unit (PMTU) discovery process. For performance reasons, PMTU black hole router detection is disabled by default for TCP/IP in Windows Server 2003, Windows XP, and Windows 2000.
When PMTU black hole router detection is enabled, if several retransmissions of a TCP segment are not acknowledged, TCP tries sending segments with the Don’t Fragment flag in the IP header of the IP packet set to 0 (which enables an IP router to fragment the TCP segment). If, as a result, a segment with the Don’t Fragment flag set to 0 is acknowledged, the TCP maximum segment size (MSS) is decreased and the Don’t Fragment flag is set to 1 (which prevents an IP router from fragmenting the TCP segment) in subsequent segments on the connection.
Enabling PMTU black hole detection increases the maximum number of retransmissions that are performed for a specific segment and can therefore decrease overall performance.
This registry entry is not present by default and must be added by using the Registry Editor tool, and then restarting Windows.
Values for EnablePMTUBHDetect
| Value | Setting |
|---|---|
0 (default) |
Disables PMTU black hole detection. |
1 |
Enables PMTU black hole detection. |
EnablePMTUDiscovery
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version Windows Server 2003, Windows XP, Windows 2000
This entry determines whether TCP uses a fixed, default maximum transmission unit (MTU) of 576 bytes for all connections that are not to destinations on a locally attached subnet, or alternatively, whether TCP attempts to detect the actual path maximum transmission unit (PMTU).
When PMTU Discovery is enabled, TCP attempts to discover the MTU, or largest packet size, allowed by the path to a remote host. By discovering the PMTU and limiting TCP segments to this size, TCP can eliminate fragmentation at IP routers along the path that connect networks with different MTUs. Fragmentation reduces TCP throughput and increases network congestion.
By default, this entry applies to all interfaces. However, you can use the Registry Editor to change the default value of this entry for one or more interfaces on this computer.
For optimal security, set EnablePMTUDiscovery to 0 in order to prevent an attacker from forcing the MTU value to a very small value and thereby overworking the TCP/IP stack.
This registry entry is not present by default and must be added by using the Registry Editor tool, and then restarting Windows.
Values for EnablePMTUDiscovery
| Value | Setting |
|---|---|
0 |
Causes TCP to use an MTU of 576 bytes for all connections to nodes outside of the local subnet. |
1 (default) |
Enables TCP to attempt to discover the actual MTU of the path to a remote node. |
IPEnableRouter
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version Windows Server 2003, Windows XP, Windows 2000
This entry determines whether IP forwarding is enabled on a computer on which the Routing and Remote Access service is not enabled. As the name IPEnableRouter indicates, manually enabling this entry enables the computer to act as a router. That is, when IP forwarding is enabled, the computer can route IP packets that it receives to nodes on all networks to which it is connected.
Values for IPEnableRouter
| Value | Setting |
|---|---|
0 (default) |
Disables IP forwarding. The host does not route IP packets. |
1 |
Enables IP forwarding. The host routes IP packets. |
A server running the Routing and Remote Access service does not use the IPEnableRouter registry entry; this entry is therefore, correctly, set to 0.
If you want to enable IP forwarding on a workstation or on a server on which you do not want to enable the Routing and Remote Access service, you must use the Registry Editor to set the IPEnableRouter registry entry to 1. Typically, a workstation or multi-homed server that is not a router should not be configured to forward packets between networks, unless it is acting as a firewall.
IPEnableRouterBackup
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version Windows Server 2003, Windows XP, Windows 2000
This entry stores a backup copy of the value that was stored in the IPEnableRouter entry when the operating system of the computer was most recently installed or upgraded. The computer uses this entry to:
Determine whether the value of IPEnableRouter has changed
Restore the previous value if the value of IPEnableRouter has changed
Do not delete this entry or change its value. If you do, you might disable the IP packet routing mechanism.
There is no default value for this entry. The computer enters a value when you install or upgrade Windows.
Values for IPEnableRouterBackup
| Value | Setting |
|---|---|
0 |
Disables storing a backup copy of the value stored in IPEnableRouter. |
1 |
Enables storing a backup copy of the value stored in IPEnableRouter. |
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\interfaceGUID
The Routing and Remote Access service uses several TCP/IP registry keys for interfaces. The entries included in this section are specific to unicast IPv4 routing features supported by the Routing and Remote Access service. For additional entries for TCP/IP interfaces, see TCP/IP Tools and Settings.
The following registry entries are located under the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\interfaceGUID.
Before you can use the registry editor to configure a registry entry located under this key, you must first determine the globally unique identifier (GUID) for the TCP/IP interface that you want to configure.
To determine the GUID for a specific TCP/IP interface
Open Network Connections, and then note the name of the LAN connection, such as “Local Area Connection.”
Open the Registry Editor (click Start, click Run, type regedit.exe, and then click OK).
In the tree view (the left pane), expand the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control \Network\{4D36E972-E325-11CE-BFC1-08002BE10318}
Under this key are one or more keys for the globally unique identifiers (GUIDs) corresponding to the installed LAN connections on this computer. Each of these GUID keys has a Connection subkey. Open each of the GUID\Connection keys, and then look for the Name setting whose value matches the name of your LAN connection from step 1.
When you have found the GUID\Connection key that contains the Name setting that matches the name of your LAN connection, write down, take a screenshot, or otherwise note the GUID value.
Use the tree view to open the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip \Parameters\Interfaces\interfaceGUID.
Right-click the interfaceGUID key you want in the tree view, and then view or configure that entry.
PerformRouterDiscovery
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\interfaceGUID
Version Windows Server 2003, Windows XP, Windows 2000, Windows 98
Note
The recommended method for configuring router discovery on a host running Windows Server 2003 or Windows XP is to set DHCP options, instead of modifying the registry.
The PerformRouterDiscovery entry determines whether Windows TCP/IP attempts to perform ICMP router discovery as a host, as defined by RFC 1256, on this interface. Enabling router discovery on a client or non-router server enables that computer to listen for Router Advertisement messages from an IP router, to send Router Solicitation messages to discover active routers on its subnet, and to switch to another router if the first router fails or the network administrator changes router preferences.
Windows does not add the PerformRouterDiscovery entry to the registry. To enable ICMP router discovery, you must add this entry (as type REG_DWORD) and set its value to one of the options listed in the following table.
Values for Enabling PerformRouterDiscovery
| Value | Setting |
|---|---|
0 |
Disables router discovery. |
1 |
Enables router discovery. |
2 (default) |
Enables DHCP-controlled router discovery. The value 2 is the default, but it is used only if the DHCP options Perform Router Discovery and Router Solicitation Address are configured. The DHCP Perform Router Discovery option is DHCP scope option 31 and the DHCP Router Solicitation Address option is DHCP scope option 32. Both are configured by using the DHCP snap-in. For more information, see “DHCP Options” in DHCP Tools and Settings. |
For ICMP router discovery to take place, in addition to configuring PerformRouterDiscovery on a client or non-router server, the following requirements must also be met:
A Routing and Remote Access router on the same subnet must be configured for ICMP router discovery, to enable it to send Router Advertisement messages to all hosts on the subnet. For more information, see “Netsh routing IP routerdiscovery context” or “ICMP router discovery options” earlier in this technical reference.
The entry SolicitationAddressBcast must be added to the registry, and its value configured. For more information, see “SolicitationAddressBcast” later in this technical reference.
PerformRouterDiscoveryBackup
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\interfaceGUID
Version Windows Server 2003, Windows XP, Windows 2000
This entry stores a backup copy of the value stored in the PerformRouterDiscovery entry (if an entry for PerformRouterDiscovery has been configured). The computer uses this entry only when IP routing is enabled and the value of PerformRouterDiscovery is 0.
Warning
This entry is used internally by the Windows operating system. Do not delete this entry or change its value. If you do, you might disable the router discovery mechanism.
There is no default value for this entry.
Values for PerformRouterDiscoveryBackup
| Value | Setting |
|---|---|
0 |
Disables storing a backup copy of the value stored in PerformRouterDiscovery. |
1 |
Enables storing a backup copy of the value stored in PerformRouterDiscovery. |
SolicitationAddressBcast
Registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\interfaceGUID
Version Windows Server 2003, Windows XP, Windows 2000, Windows 98
Note
The recommended method for configuring router discovery on a host running Windows Server 2003 or Windows XP is to set DHCP options, instead of modifying the registry.
The SolicitationAddressBcast entry, as defined by RFC 1256, determines whether Windows sends router discovery messages as broadcasts rather than as multicasts on this interface. Enabling router discovery on a client or non-router server computer lets that computer listen for Router Advertisement messages from a router and lets that computer send Router Solicitation messages to discover active routers on its subnet and to discover the unavailability of previously available routers that are currently down.
Windows does not add the SolicitationAddressBcast entry to the registry. To specify how router solicitation messages are sent, you must add this entry (as type REG_DWORD) and set its value to one of the options listed in the following table.
Values for Enabling SolicitationAddressBcast
| Value | Setting |
|---|---|
0 (Default) |
Enables the sending of router solicitation messages to the all-routers multicast group (224.0.0.2). This is the recommended option. |
1 |
Enables the sending of router solicitation messages as limited broadcast messages by using the IP address 255.255.255.255. The value 1 is not recommended because it causes all clients to broadcast router solicitation messages, creating a large volume of unnecessary broadcast traffic that must be processed by other clients. |
For ICMP router discovery to take place, in addition to configuring the value for this entry, the following requirements must also be met:
A Routing and Remote Access router on the same subnet must be configured for ICMP router discovery, to enable it to send Router Advertisement messages to all hosts on the subnet. For more information, see “Netsh routing IP routerdiscovery context” or “ICMP router discovery options” earlier in this technical reference.
The entry PerformRouterDiscovery must be added to the registry, and its value configured. For more information, see “PerformRouterDiscovery” earlier in this technical reference.
Note that PerformRouterDiscovery option 2 enables DHCP-controlled router discovery, but only if the DHCP options Perform Router Discovery and Router Solicitation Address are configured.
Related Information
The following resources contain additional information that is relevant to this section.
Command-Line Reference for Windows Server 2003, Standard Edition
“Parameters Configurable Using the Registry Editor” in Microsoft Windows Server 2003 TCP/IP Implementation Details