Fwd: weird connection issue

An after hours user contacted me and said they where working on the system
and the client access screen went blank (as if disconnected), and could not
get back on. I had them reboot and try again. Client access starts (java)
and presents the windows to enter user and password. After user enters
criteria and hits OK, the signon window closes leaving them with a blank
green screen. They never get green screen login. The communication menu
option shows as trying to connect but nothing happens. I varied off/on
their workstation device but did not help.

Any active connections didnt seem to be affected. I had a session open and
did not experiance the issue. When i rebooted my computer and tried to
connect i got the same issue as the user after their reboot.

I was able to get onto the prod box via console and was able to TELNET to
our DR box, but could not TELNET from DR to PROD (wanted to exclude client
access as an issue).

No error messages on qsysopr and nothing in DSPLOG.

I re'ipled the PROD box and everything is working fine now.

Any ideas what might be the cause or where to look for the cause? I'd hate
for this to happen during normal working ours. Out nextwork people say its
the iseries. I was thinking it was some kind of port issue.