[c-nsp] 2950-48-SI arp problems ?

[Brian Turnbow]

I'm not sure I followed you here. 
Is it the gateway or the host that loses arp ?
Your host losing it's arp table should not effect inboud sessions.
If your gateway maintains arp and packets don't get to the host 
It's not your host without arp that has a problem but your switch that 
Is not forwarding to that mac for some reason. Check to see if the hosts
Mac is listed in the switches forwarding table.  
You can try to raise the mac address aging time to see if it helps. 

Regards
Brian



-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of matthew zeier
Sent: martedì 21 dicembre 2004 18.09
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] 2950-48-SI arp problems ?

I have two 2950-SIs running Version 12.1(22)EA2.  Switch config is pretty
simple:

core1/core2 (6905) -- dot1q trunk -- access4 (6905) --- trunk --- 2950 .


Hosts on the 2950 are able to connect to the Internet, however, if idle for enough time (something between minutes and less than an hour), the host's ARP table becomes empty and the gateway is unable to ping/reach the host (so inbound connections are lost).

Running 'tcpdump' on one of the Linux hosts shows that there aren't any packets from the gateway reaching the host.  If the host pings the gateway, everything works - inbound connectivity is restored.

I've used three different computers (PC laptop & windows, supermicro & redhat, mac) with the same problem.  If I replace the 2950 with a 2948, the problem appears to go away.

Did I miss the "ip work-all-the-time enable" option?  The 2950's trunk looks
like:

interface GigabitEthernet0/1
 switchport trunk native vlan 2
 switchport mode trunk
!




--
matthew zeier, Sr. Network Engineer  | "Nothing in life is to be feared.
InteleNet Communications, Inc.       |  It is only to be understood."
(949) 784-7904                       |       - Marie Curie 

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