Azure App Service - call to VNET service is not working

Question

I have a App service which is in VNET1 and this VNET1 is connected to VNET2 on other network with Point-to-Site Connection. My App Service is connected to VNET1.

These two VNETs are connected and tested. those are working fine.

when i ping (tcpping) from App Service console to VNET1 and VNET2 IP its working fine. Also Curl Request is working fine.

But when i call the Same URL from App service page. its showing Request Time out Error.

Any Suggestions why this is not working?

Answer 1

There are many things that can prevent your app from reaching a specific host and port. Most of the time it is one of three things:

There is a firewall in the way If you have a firewall in the way, you will hit the TCP timeout. That is 21 seconds in this case. Use the tcpping tool to test connectivity. TCP timeouts can be due to many things beyond firewalls but start there.

DNS is not accessible The DNS timeout is three seconds per DNS server. If you have two DNS servers, the timeout is 6 seconds. Use nameresolver to see if DNS is working. Remember you can't use nslookup as that does not use the DNS your VNet is configured with.

Invalid P2S IP range The point to site IP range needs to be in the RFC 1918 private IP ranges (10.0.0.0-10.255.255.255 / 172.16.0.0-172.31.255.255 / 192.168.0.0-192.168.255.255). If the range uses IPs outside of that, then things won't work.

For more details, refer this Troubleshooting steps and see if that helps.