Don’t add hostkey to known_hosts for SSH

hostsssh

I want to connect to a host via SSH but I don't want the hostname to be added to my ~/.ssh/known_hosts.

How can I do that?

Best Answer

If you want this behavior because you're working with cloud servers (AWS EC2, Rackspace CloudServers etc.) or you're constantly provisioning new images in Vagrant you may want to update your SSH config instead of adding bash aliases or more options on the command line.

Consider adding something like:

Host *.mydomain.com 
  StrictHostKeyChecking no
  UserKnownHostsFile /dev/null
  User foo
  LogLevel QUIET

Use as strict as regex for host as possible to be secure.
Setting the LogLevel to QUIET will keep the Warning which Guillaume mentioned from showing up

Related Solutions

Linux – How to stop adding IP from EC2 to known_hosts for ssh

This is done to prevent Man in the Middle attacks. Disabling it would disable basic functionality of the ssh tools.

You may want to keep a copy of your .ssh/known_hosts file without the entries and replace it when you are done.

Macos – /.ssh/known_hosts file does not exist? (Mac)

The article Failed to add the host to the list of known hosts has this advice :

Check directory permissions

The ssh client needs to be able to write to files in the .ssh directory :

ls -ld ~/.ssh

If the permissions aren't correct then run this to fix them:

chmod 0700 ~/.ssh

Check file permissions

Check if the files in the .ssh directory have read-write permissions :

ls -l ~/.ssh

If they don't, run :

chmod 0600 ~/.ssh/*

Remove ACL flags

If the ssh client still cannot write to the folder, one needs to clear the ACL flags :

chmod -R -a# 0 ~/.ssh

Best Answer

Related Solutions

Linux – How to stop adding IP from EC2 to known_hosts for ssh

Macos – /.ssh/known_hosts file does not exist? (Mac)

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