Function app with NAT Gateway & Public static IP is configuration

Question

Function app with NAT Gateway & Public static IP is configure, why Public IP when pinged is not responding from an outside network

Answer 1

@Neela ,

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

Points to Note :

• ICMP protocol is not supported by NAT Gateway. Ping using ICMP protocol isn't supported and is expected to fail.
  • See : NAT gateway configuration
• NAT Gateway is used to provide Outbound connectivity from the resource in Subnet to Internet
  • It is not designed for Inbound connectivity
  • If you attempt to make inbound connection, it will fail - even if it's TCP or UDP

May I ask what is your requirement here?

• The primary use case of having a NAT Gateway in a VNET Integrated Function App is to have a fixed IP Address while the Function App makes outbound calls.
• Without NAT Gateway, the Function App's Default outbound IPs are used
  • These are random IPs and is dynamic
  • i.e., can change over time
• With NAT Gateway, only the Public IPs associated with the NAT gateway are used
  • These are fixed IPs and do not change over time

See : Control Azure Functions outbound IP with an Azure virtual network NAT gateway

Virtual network address translation (NAT) simplifies outbound-only internet connectivity for virtual networks. When configured on a subnet, all outbound connectivity uses your specified static public IP addresses. An NAT can be useful for apps that need to consume a third-party service that uses an allowlist of IP address as a security measure.

Please let us know if we can be of any further assistance here.

Thanks,

Kapil

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