Issues changing default ssh port number

I just attempted to replicate this, so please bear with me while I walk through my process.

First, I deployed a brand new Ubuntu 22.04 LTS server, and the first thing I did once I connected was updating via: apt update && apt upgrade -y. This took a little while and alerted me to some "reboot required" upgrades but none related to SSH/SSHD so I moved on.

I modified my SSH Config located /etc/ssh/sshd_config file to specifically use port 2222, and after saving/closing out of the file, I restarted the SSH daemon systemctl restart sshd. I made sure to setup some basic UFW firewall rules:

• sudo ufw default allow outgoing
• sudo ufw default deny incoming
• sudo ufw allow 22 (in case the custom SSH port failed)
• sudo ufw allow 2222 (my test custom port)

After making these changes I updated my UFW rules using the command: yes | sudo ufw enable. I exit'd out of my instance and then rebooted through Cloud Mananager, and then was able to successfully connect to my server using the command: ssh root@$IP_ADDRESS -p 2222.

When you attempt to connect using your custom/specified port what error message do you receive?

One great way to troubleshoot SSH issues is to use the "Verbose" option flag: ssh root@$IP_ADDRESS -p $PORT -v. You can increase the verbosity by increasing this to -vv and -vvv to get increasingly granularr details about what stage of the connection is failing.

I usually have to sudo reboot before it takes effect.. make sure it's listed in the firewall you use (UFW is a good one) Being a VM might make a difference but i'd try it.

I've blown away that VM since. I'm spinning up a new one now so will test again.

I tired all of the above steps while using UFW so not sure why it wouldn't work. Error is standard - unable to connect over port xxxx

Thanks for the replies

Does your ssh daemon bind on port 2222 at all? Since I've the same issues and I found ssh daemon doesn't bind on port different than 22, even I've modified sshd_config and explicitly said the the port will be different.

lsof -i :2222

what is the output?