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From: drs@bnlux0.bnl.gov (David R. Stampf)
Newsgroups: comp.dcom.sys.cisco
Subject: Dealing with remote routers
Message-ID: <2063@bnlux0.bnl.gov>
Date: 15 Aug 90 20:17:22 GMT
Organization: Brookhaven National Lab
Lines: 28

We are experiencing a tough problem in x-country communications. A connection
is set up between two unix hosts which are quite remote from each other.
Between them are several networks, some of which are connected by cisco
routers. This connection is in operation for a long period of time, then
suddenly disappears, killing the session and annoying the users. This
occurs intermittantly, >1 <20 times a day.

Some detective work with ping and traceroute shows that an intermediate
cisco router is (for no discernable reason) sending a "Host unreachable"
icmp message at infrequent and unpredictable intervals. Querying the 
router does not indicate the loss of a route,nor the toggling of an 
interface.

I've discussed this on other mailing lists, and found someone who had a
similar problem and solved it by turning off the icmp unreachable messages
on that interface. He did not understand why the messages appeared, but
it did solve his problem. When I discussed this solution with the owners
of the router, they didn't seem too enthusiastic about making such a change
in that it may break traceroute (that being more important than telnet ;-)).

So my questions are, 1) Does anybody know any other reasons for a cisco
router to generate this message, and 2) (the hard question) how do you
deal with a router many levels removed from you whose operation is having
a major impact on your operation?

	Thanks for any help or enlightenment.

	< dave