How to fix ssh_dispatch_run_fatal?

Table of Contents

On a Linux 8 system with FIPS enabled, connecting to a Linux 6 system fails, ssh -v displays the following message

ssh_dispatch_run_fatal: Connection to XXX port 22: invalid argument


The simplest solution is to delete file /etc/ssh/moduli on the Linux 6 system serving as sshd backend.

The same workaround is applicable for other Linux 8 FIPS clients connecting to non-FIPS servers using this key exchange method.

Understanding SSH known_hosts File

Exploring ServerAliveInterval ClientAliveInterval in SSH

Use SSH Private Key to Login Linux Without Password