site-to-site VPN only work 1 way

Question

here the details of my network
on-premise network: 192.168.1.0/24
azure virtual network 10.0.0.0/16

i had successfully setup the site-to-site VPN.
but only works 1 way.
from Azure VM able access to my on-premise device.

but from my on-premise device unable access to Azure VM.

What is the cause?

thank you

Answer 1

Hello Ben Chio,

Thanks for your question

There are many possibilities why. Here's some I would recommend checking:

• On azure if route table includes 192.168.1.0/24 and if firewall has a route to 10.0.0.0/16 via the VPN tunnel (Next hop: Your VPN interface)
• Check firewall rules allowing traffic to Azure subnet
• Review NSG rules and see if Source: 192.168.1.0/24 is allowed
• Verify your on-premise IP is correct

You could test your commands using:

# Test connectivity 
ping VM-IP]  

ip route   

traceroute [VM-IP] 

See: https://learn.microsoft.com/en-us/azure/vpn-gateway/vpn-gateway-troubleshoot-site-to-site-cannot-connect?source=recommendations

You can mark it 'Accept Answer' and 'Upvote' if this helped you

Regards,

Abiola