Problem with OpenSSH

Hi !

I've got a remote machine that is some 200 mile away. I've just re-installed
the machine from scratch a month ago with tao 1.0 up to date. (I need 1.0
because it's a dell with some raid card not yet fully supported in 4).

Since a couple of week, sometimes, I cannot login remotly. I get the
password prompt, I enter my password, and it hangs there. ssh -v didn't show
anything usefull. When that happens, I have to tell the IT guy there to
reboot the machine. After that it's ok generally until the next day, where
it starts again to hang.

I suspected a cron running at night or something like that, but the jobs
running at night runs ok from my shell. I didn't see nothing intelligent in
any log file.

One day, I stayed logued in running top, and the next day, I saw that the
uptime was 5 (very anormal for that machine usually having uptime of 0.2 or
the like). So I suspect a lack of ressource of some sort, but I can't point
my finger on it.

The machine has plenty of ram (1 gig, 2 gig swap), plenty of scsi disk space
on all partitions. It's only a web server with mysql and some other things,
nothing major...

So I'd like some ideas to where to look !

Nicolas