Strange behavior of Catalyst4006

Erik Amundson erik at myevilempire.net
Tue Jun 29 01:27:55 UTC 2004


It is possible that this issue is being cause by the customer's firewall as
well.  Every Ethernet cable has two ends. :)  I would check and see if the
customer's firewall log says anything.  I believe doing a shut/no shut on
the Cat 4006 causes the Ethernet link to 'flap' on the port, causing the
interface to totally reset on both ends.  This could be clearing errored
conditions on both sides.  Is there anything interesting in the 4006 log?
Have you done a 'show interface fa4/41' when the interface in broken to see
if it has any reasoning for the failure?

One other thing you could do it a 'no cdp enable' on the interface.  You
really won't get any cdp information from a firewall anyways...at least you
shouldn't* get any. :)

- Erik


-----Original Message-----
From: owner-nanog at merit.edu [mailto:owner-nanog at merit.edu] On Behalf Of Joe
Shen
Sent: Monday, June 28, 2004 8:01 PM
To: nanog at merit.edu
Subject: Strange behavior of Catalyst4006




Hi,


We met a strange problem with Catalyst 4006 when provideing leased line
service to one of our customers.


Catalyst4006 ------------  Customer's firewall ---------------Customer's
Intranet
                  

The customer is allocated a Class C address block 192.168.5/24.  And , they
connect their network to our
network  by using a firewall.  The Interface on Cata4006 is set up as "no
switchport", and inter-connecting 
subnet is configured between Cata4006 and firewall
interface(10.10.1.122/30).

Static route is used on Catalyst4006  to designate route  to customer's
intranet address. ( ip route 192.168.5.0 
255.255.255.0 10.10.1.124 ). Customer setup their email server at
192.168.5.7, dns server at 192.168.5.1,
 web server at 192.168.5.9.  

At the very begining all system works fine. After sometime  they said they
could not  acces their email/web/dns 
server from host outside their company's network. But, when we telnet to
Cata4006, we could 'ping' 
192.168.5.7, but if we move to host in NOC ping failed all the time. ( ping
to server is allowed on firewall). At the same 
time, their intranet host could access our network.

We restart ( shut; noshut) the fastethernet interface on Catalyst4006, and
then servers' network access recovered.

The phenomon comes up frequently, and our customer said this is a bug with
catalyst4006. But, to my understanding, 
if this is a bug to catos, it should not only affact only three servers.
But, why it could be solved by restart catalyst interface?

Would you please do some help? ( I attach system info below)

Joe Shen



======================-=

4006#sh version
Cisco Internetwork Operating System Software 
IOS (tm) Catalyst 4000 L3 Switch Software (cat4000-IS-M), Version
12.1(12c)EW1, EARLY DEPLOYMENT RELEASE 
SOFTWARE (fc1) TAC Support: http://www.cisco.com/tac Copyright (c) 1986-2002
by cisco Systems, Inc. Compiled Thu 24-
Oct-02 23:05 by eaarmas Image text-base: 0x00000000, data-base: 0x00CA7368

ROM: 12.1(12r)EW
Dagobah Revision 63, Swamp Revision 24

4006-wulin uptime is 41 weeks, 12 hours, 34 minutes
System returned to ROM by power-on
System restarted at 05:40:46 RPC Mon Sep 15 2003
System image file is "bootflash:cat4000-is-mz.121-12c.EW1.bin"

cisco WS-C4006 (XPC8245) processor (revision 5) with 524288K bytes of
memory. Processor board ID FOX05200BRH Last 
reset from PowerUp 144 FastEthernet/IEEE 802.3 interface(s) 2 Gigabit
Ethernet/IEEE 802.3 interface(s) 403K bytes of non-
volatile configuration memory.

Configuration register is 0x2102

4006#


4006-wulin#sh run int f4/41
Building configuration...

Current configuration : 141 bytes
!
interface FastEthernet4/41
 no switchport
 ip address 10.10.1.213 255.255.255.252
 duplex full
 speed 100
end

4006#


===============================================




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