Keep Alive SSH Sessions

Last Updated on July 19, 2024

To keep an SSH connection alive, you can modify your SSH configuration to send periodic keepalive messages. Here are a few methods to achieve this:

Method 1: Modify the SSH Client Configuration

1. Edit the SSH client configuration file (/etc/ssh/ssh_config or ~/.ssh/config):

   nano ~/.ssh/config
   

2. Add the following lines to send keepalive messages every 60 seconds:

   Host *
       ServerAliveInterval 60
       ServerAliveCountMax 3
   

   • ServerAliveInterval specifies the interval in seconds between keepalive messages.
   • ServerAliveCountMax specifies the number of keepalive messages that can be sent without receiving a response from the server before the connection is terminated.

Method 2: Modify the SSH Server Configuration

1. Edit the SSH server configuration file (/etc/ssh/sshd_config):

   sudo nano /etc/ssh/sshd_config
   

2. Add or modify the following lines to keep the server alive:

   ClientAliveInterval 60
   ClientAliveCountMax 3
   

   • ClientAliveInterval specifies the interval in seconds that the server will wait before sending a null packet to the client to keep the connection alive.
   • ClientAliveCountMax specifies the number of client alive messages which may be sent without receiving any messages back from the client.
3. Restart the SSH service to apply the changes:

   sudo systemctl restart sshd