CODEWITHSUNDEEP
azuretcpportazure-virtual-machine
Pavan
Pavan

Reputation: 1083

Connection to azure virtual machine public port is timed out

I am using Azure Virtual Machine (Windows Server 2008 R2 image) provided from the gallery and created Public port and private port using the portal. I did remote log in to VM and I run a TCP server application inside VM (TCP server binds to the private port of the VM). Problem I face is that I can not connect it through the public IP and port (from external machine). I have created a inbound rule in VM's Firewall, where I enable connection to the Private port of VM. I tried recreating the VM, also the new ports. Still problem persists. One more thing I observed is that my TCP Client is able to connect to RemoteDesktop port of the VM also the PowerShell port. But does not connect to the port that I created through the portal. Pls suggest what can be wrong?

Note: I also observed some weird behavior. I enabled all ports for my TCP Server app in Inbound rule of firewall and found that some unknown IP (was similar to azure internal IP) is connecting to my server. Why it is happening?

Upvotes: 1

Views: 2386

Answers (1)

Sowmya K R
Sowmya K R

Reputation: 166

I would like to understand as to how you are trying to connect with the Virtual Machine, using RDP or trying to test the connectivity, for example, using Port Ping.

Endpoints for RDP and Powershell are configured by default. So if you are trying to connect using Remote Desktop, you can directly connect to the VM using MSTSC from Run and provide the IP of the VM followed by the Port Number using the below format xx.xx.xx.xx:3389

However if you would like to test the connectivity to the VM, I suggest you to use Port Ping instead of ICMP ping since ICMP traffic is blocked by the Azure load balancer and the ping requests timeout. While Ping.exe uses ICMP, other tools such as PsPing, Nmap, or Telnet allow you to test connectivity to a specific TCP port.

On the other hand, after creating the VM, you can add endpoints additionally as needed. You can also manage incoming traffic to the public port by configuring rules for the Network Access Control List (ACL) of the endpoint.

  • The private port is used internally by the virtual machine to listen for traffic on that endpoint.
  • The public port is used by the Azure load balancer to communicate with the virtual machine from
    external resources. After you create an endpoint, you can use the network access control list (ACL) to define rules that help isolate and control the incoming traffic on the public port. For more information, see About Network Access Control Lists.

Upvotes: 1

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