[CentOS] logging in

This is.... odd.

We're seeing a *lot* of sshd[8400]: Timeout, client not responding. So I'm trying to find out whose client is having issues. Trying to figure that, after processes are gone, I tried looking in lastlog, which is where it gets odd. lastlog shows root coming in, and it shows a security account coming in... years ago.

I see one of our users logging in a goodly number of times... but lastlog doesn't show him. I just logged in as myself, no password, using keys... and lastlog doesn't show me, or my manager, or anyone else.

Does anyone have any idea why lastlog's not recording *all* logins?

mark