Unable to dialout via Microsip on Azure VM

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Hello @Vamshi Krishna Dachavaram I hope you are doing well,

Having a public IP assigned to the Azure VM does provide explicit outbound Internet connectivity, but for MicroSIP/VoIP, you also need to verify the SIP signaling and RTP media traffic. Azure supports outbound UDP from a VM with an instance-level public IP. (learn.microsoft.com)

I recommend checking the following:

1. Verify basic Internet connectivity from the VM and confirm that the SIP provider's hostname/IP is reachable.

Check the NSG associated with the VM NIC/subnet and make sure outbound UDP traffic required by your SIP provider is allowed.

Check Windows Firewall on the VM. Make sure MicroSIP is allowed to communicate over the required UDP ports.

Verify the SIP provider's ports. SIP commonly uses UDP/TCP 5060 or TLS 5061, while RTP uses a separate UDP port range. The exact RTP range depends on your provider.

Check NAT/SIP settings in MicroSIP. If the provider requires STUN, configure the appropriate STUN server and verify the NAT traversal settings.

1. Capture traffic with Wireshark on the VM while attempting a call. Check whether SIP REGISTER/INVITE packets leave the VM and whether responses return.

You can also confirm the VM's effective outbound configuration in Azure. A directly assigned public IP provides explicit outbound connectivity, while NAT Gateway or Load Balancer outbound rules are alternative methods. (learn.microsoft.com)

If basic Internet access works but MicroSIP cannot register or complete calls, the next important information would be the SIP provider, SIP port, RTP port range, MicroSIP error message, and whether the account successfully registers. That will help determine whether the issue is Azure networking, Windows Firewall, NAT traversal, or the SIP provider.

References:

Azure outbound connectivity for VMs

Azure Public IP addresses

Troubleshoot Azure outbound connectivity

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