Showing posts with label openssh. Show all posts
Showing posts with label openssh. Show all posts

25 September 2023

Impact of new openssh 9.3p1 on Solaris 11.4.60

When connecting to an old server you may see

-bash-5.2$ ssh g0083
Unable to negotiate with 192.168.100.83 port 22: no matching host key type found. Their offer: ssh-rsa,ssh-dss

or if you try to connect from an old system to Solaris 11.4.60 or newer

-bash-4.4$ ssh g0049
no hostkey alg

This is because the new openssh version on Solaris 11.4.60 has sha-1 hash disabled by default.
It is recommended to update your old systems to newer versions.

On Solaris 11.3 you need to:
pkg install openssh
pkg set-mediator -I openssh ssh



If this is not possible as a workaround you can enable sha-1 on the new Solaris server
for the target systems in /etc/ssh/ssh_config and/or sshd_config

Host g0083
HostKeyAlgorithms +ssh-rsa
PubkeyAcceptedAlgorithms +ssh-rsa