pump seems to be trying to renew it lease several times a second, winding up in a situation that looks much like a DOS attack. It seems that when the lease time == 0 (infinite lease) it trys over and over. We have disabled pump on all local linux boxes, but this is still a serious problem.
I can't reproduce this -- could you test pump-0.7.8 (from ftp://people.redhat.com/ewt/) and see if this still happens?