OpenSSH versions prior to 8.5(ex:- 8.0), TOS value was set for ssh server and client after authentication phase is over. This was changed from OpenSSH version 8.5. As per release note of OpenSSH version 8.5, TOS value of sshd(server) and ssh(client) can be set before the TCP connect. I was checking the OpenSSH version 9.0, I could see that only for client TOS is getting set before TCP connect. But, for server packets TOS is still getting set only after authentication. Though as per release note of version 8.5 it's mentioned that TOS can be set for both server and client in the connection phase.
*Release note:-
- ssh(1), sshd(8): set the TOS/DSCP specified in the configuration for interactive use prior to TCP connect. The connection phase of the SSH session is time-sensitive and often explicitly interactive. The ultimate interactive/bulk TOS/DSCP will be set after authentication completes. https://www.openssh.com/txt/release-8.5*
Can someone please clarify me why for server TOS is not set before server starts listening to ssh port? I have checked the man page if there is any new configuration added for setting DSCP value during TCP connect, but there is none.