Putty SSH Timeout – Troubleshooting Connection Issues on Azure VM

azuredebianputtysshvirtual-machines

I just came out with a nice Debian 9 "Stretch" Virtual Machine hosted with Microsoft Azure. I've already used PuTTY, PuTTYgen and Pageant to connect with ssh to it and i've saved all this configuration into the PuTTY's startup window.

Once connected i've managed the VM, created the authorized_keys file and copied my public key in it under the .ssh directory.

But this afternoon, while running my PuTTY again, it isn't able to reach the VM and throw me a "timed out" connection after some time.

I've already tried :

Restart the VM via the Azure Portal
Redeploy the VM via the Azure Portal
Running with and without Pageant
Checking over and over the configuration …

What I can't do :

Reset user's credentials and ssh configuration thought the Azure Portal (Missing VMForLinuxAccess extension)
Use Azure CLI
Change VM's configuration (I don't own the VM rights)

Have you any idea how to troubleshoot this problem ?

Thanks in advance.

Best Answer

Just put comments as an answer.

Have you any idea how to troubleshoot this problem?

You could telnet VMpublicIP with port 22 to check if network traffic blocking. Also, you can capture the network traffic packages to analyze the network traces between the client and server via tool Wireshark or Network monitor.

Moreover, you can find the Troubleshoot SSH connections to an Azure Linux VM and Detailed SSH troubleshooting steps for issues connecting to a Linux VM in Azure.

Related Solutions

Ssh – created pub/priv keys using putty, created .ssh folder and authorized_keys, still not working

Check your /var/log/secure or /var/log/auth on the Linux server for information why the key is not accepted.

Also, is the .ssh directory in the homedir of (and owned by) the user you are using to connect?

If you want to connect with the root user, it might be disabled in /etc/ssh/sshd_config.

Ssh – How to automate SSH login with password

Don't use a password. Generate a passphrase-less SSH key and push it to your VM.

If you already have an SSH key, you can skip this step… Just hit Enter for the key and both passphrases:

$ ssh-keygen -t rsa -b 2048
Generating public/private rsa key pair.
Enter file in which to save the key (/home/username/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/username/.ssh/id_rsa.
Your public key has been saved in /home/username/.ssh/id_rsa.pub.

Copy your keys to the target server:

$ ssh-copy-id id@server
id@server's password:

Now try logging into the machine, with ssh 'id@server', and check-in:

.ssh/authorized_keys

Note: If you don't have .ssh dir and authorized_keys file, you need to create it first

to make sure we haven’t added extra keys that you weren’t expecting.

Finally, check to log in…

$ ssh id@server

id@server:~$

You may also want to look into using ssh-agent if you want to try keeping your keys protected with a passphrase.

Best Answer

Related Solutions

Ssh – created pub/priv keys using putty, created .ssh folder and authorized_keys, still not working

Ssh – How to automate SSH login with password

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