SQL 2008 Remote connection checklist
I don't know why SQL document didn't put all pieces infomation together. Here is the full list to check:
1. Ensure machineName\SqlInstanceName is correct
2. Open "Sql Server Configuration Manager",
under "SQL Server Services", ensure "SQL Server" and "SQL Server Browser" is running;
under "SQL Server Network Configuration"->"Protocols for server", ensure "Named Pipes" and "TCP/IP" are enable
3. Open SQL Server Management Studio, right click server->property, in the "Server Properties", go Connections
check "Allow remote connections to this server" (Question: why this step would not enable the network protocols in step 2?)
4. Open Windows Firewall configuration, add two exceptions for Sql server (TCP 1433) and Sql browser (UDP 1434)