For some special users like Adminsitrators, who needs to SSH directly into the compute instead of submitting to the scheduler with using root, you may want to do the following:

At the Compute Node

# vim /var/spool/pbs/mom_priv/config

Find the $restrict_user_exceptions

$clienthost 192.168.x.x
$clienthost 192.168.y.y
$restrict_user_maxsysid 999
$restrict_user True
$restrict_user_exceptions user1
$usecp *:/home/ /home/

Restart the PBS Service

# /etc/init.d/pbs restart