How to prevent "Write Failed: broken pipe" on SSH connection?

What can I do to configure SSH on both client and servers to prevent Write Failed: broken pipe errors? It often occurs if you sleep your client computer and resume later.

Solution 1:

I have tried this in /etc/ssh/ssh_config for Linux and Mac:

Host *
ServerAliveInterval 120

This is how often, in seconds, it should send a keepalive message to the server. If that doesn't work then train a monkey to press enter every two minutes while you work.

You could set either ServerAliveInterval in /etc/ssh/ssh_config of the client machine or ClientAliveInterval in /etc/ssh/sshd_config of the server machine. Try reducing the interval if you are still getting the error.

Configuration for a single user can be set in file ~/.ssh/config both on the server and client side. Make sure the file has correct permissions chmod 644 ~/.ssh/config.

Solution 2:

SSH sessions may break due to numerous and possibly unavoidable reasons.

A useful utility which can be used to mitigate problems caused by this is called screen. Screen is a powerful utility that allows you to control multiple terminals which will stay alive independently of the ssh session. For example, if you run screen in an ssh session you will see a new terminal open and you can use that to run jobs. Lets say your ssh session dies in the process. Running screen -d then screen -r will reopen the last session and you will be able to continue from there. Make sure you read some of the documentation before using it.

Solution 3:

Client configuration

Try creating the file:

~/.ssh/config

Add the contents:

Host *
  ServerAliveInterval 30
  ServerAliveCountMax 5

Now ssh to your server and see if your problem is fixed. ClientAliveInterval option is only useful when configuring the ssh server (aka sshd), it does not change a thing on the ssh client side, so don't use it in the above configuration file.

This will send a hello-are-you-there signal to the server if no packets have been received in the preceding 30 seconds (as specified above). However, if the number of consecutive hello-are-you-there signals reach ServerAliveCountMax then ssh will disconnect from the server. This value is defaulting to 3 (so 3*30 = 90 seconds without server activity), increase it if it suits your needs. There are alot more config options to the .ssh/config file and you could read:

Using an SSH Config File

For more information on other options. You may not want to apply this to every server you connect to which this example will. Or restrain it to only a particular server by replacing the line Host * with Host <IP> (replace by an IP address, see ssh_config man page).

Server configuration

Similarly you can tell the server to be gentle with your clients. The configuration file is /etc/ssh/sshd_config.

ClientAliveInterval 20
ClientAliveCountMax 5

You can either deactivate it by setting ClientAliveInterval to 0 or tweak ClientAliveInterval and ClientAliveCountMax to set a maximum ssh client inactivity without responding to the probes. One advantage of this settings over TCPKeepAlive is that the signals are sent through the encrypted channels, so it is less likely to be spoofable.