erratic network problems (fwd)

===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================

---------- Forwarded message ----------
Date: Mon, 04 Oct 1999 16:39:22 -0600
From: Pete Siemsen <address@hidden>
To: address@hidden, address@hidden, address@hidden
Subject: erratic network problems

Foothills users have experienced erratic network problems since
Thursday of last week, when we shut off our T3 link to the Internet.
We just discovered what the problem was, and fixed it.

The Foothills router, flr.ucar.edu, was receiving a flapping default
route from the internetr and vbnsr routers.  Periodically, the flr
router had no default route for 10-15 seconds at a time.  This problem
only affected traffic from Foothills to the outside world; traffic
to/from the Mesa Lab was not affected.

As you can imagine, this one was "interesting" to debug, because the
problem appeared and disappeared fairly quickly, and happened only on
Foothills machines trying to talk to the outside.  When we were first
told about the problem, we checked and found nothing, so we assumed
transient Internet problems outside NCAR were the culprit.

Routing is stable now.  We apologize for the problem.

-- Pete