![]() ![]() Is that right?įind out which application is listening on the SSH port using netstat. ![]() At the same time, the netstat command shows that the port is active and listening. Even directly on the server it is not possible to detect a port as open using the nmap and nc. I'm not sure I understood the situation correctly. Then test from the other computer using the nc to see if the availability of the SSH port has changed. There is an easy test to verify whether the SSH traffic is blocked by a local firewall on the server or not. For example, it is enough to have an incorrect rule order (a deny rule above an accept rule) or use the wrong profile (public/office/home) to render the rule allowing SSH is ineffective. Server keys must always be present and set correctly, otherwise neither remote nor local SSH connections will work.įrom all your description, it looks like a problem of the local firewall on the server, unless there is another one between the two computers. Nmap done: 1 IP address (1 host up) scanned in 0.02 secondsĪs for SSH keys, I assume you know what you're doing. Nmap scan report for localhost (192.168.1.50) Response: Starting Nmap 7.80 ( ) at 21:27 CET Response: Connection to 192.168.1.50 22 port succeeded! You can use other commands instead of the telnet to see via network the port 22 is opened. Right output should be like this: Trying 192.168.1.50. Verify that port 22 on the Ubuntu server is visible as open from the outside. Replace the 192.168.1.50 by real address of your server. Use another network node to check the situation from outside. Verify connectivity to Ubuntu server from another PC The w command shows 1 extra line for each SSH connection to the same server. You should connect your account back to the same server. Let the detected address be 192.168.1.50. Preparation: Get/verify Ubuntu server own ip address by command ip addr. Right command response example is: -A ufw-user-input -p tcp -m tcp -dport 22 -j ACCEPT Or second possibility how to find the TCP 22 port rule with less strict filter: sudo iptables-save | grep "22" Is there a rule on the firewall allowing access to port 22? sudo iptables-save | grep "\-dport 22" Right netstat answer shoud be like this: tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTENING 1702/sshd: /usr/sbi In case the netstat command is not installed, install it: sudo apt-get update Is the SSH daemon service listening on the TCP port 22? sudo netstat -lntp | grep 22 ![]() You must see a green dot at the left edge and status message Active: active (running). Is the SSH daemon service running? sudo systemctl status rvice In case all tests are OK,the problem is on Windows side. Sometimes a problem arises when the SSH versions or the server-side and client-side versions of security algorithms mismatch.īut try following tests concerning Ubuntu server. I run the following command in Windows Powershell: ssh -p /.ssh/config) or the read permission is missing. Both my Windows and iOS SSH settings have not changed since the update yet neither work. I checked in ~/.ssh/authorized_keys and keys for all the intended devices are still there. With my SSH configuration, I require both a password and an SSH key to join, and my gut tells me the SSH key is the issue. ufw has my ssh port enabled still as well. I can tell the server's networking is not the issue, as all the other services I'm running on it such as a website, pi-hole, and minecraft server are running fine and can be connected to, and pinging to and from the server behaves as expected. However, I am still unable to connect via SSH. I used systemctl start ssh to start the ssh server back up, as it had apparently not restarted. After the second reboot, I was no longer able to connect via ssh. I am running Ubuntu 22.04.1 LTS on a server, and this morning I ssh'd in to it from the Termius app on my phone to run update and upgrade as per usual, then rebooted it twice to install a kernel upgrade. ![]()
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