We have a Windows VM with our application front end trying to connect to a Linux VM that has the backend. Both VMs are within a VNET on separate subnets with their own NSGs. The VNET is part of a site to site VPN and has an assigned address range and a VPN gateway. Both VMs are assigned private addresses from that range. We can connect from the front end Windows VM to the backend
Linux VM via SSH (Port 22) without issue.
The backend server for our application is up listening on TCP 10018. The NSG tied to the backend's subnet has an allow rule for any source to connect via any protocol to port 10018. However, when the front end client tries to connect the requests are getting stuck in State = SVN_SENT. We used IP Flow to verify NSG's are allowing the traffic. When using Network Watcher > Connection Monitor to test wereceive
{"origin":"Local","severity":"Error","type":"NoListenerOnDestination","context":[]}However, we can run netstat on the Linux VM and see that the app server is listening.
We are at a loss and any help is greatly appreciated.