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

[matthew zeier]

> I'm not sure I followed you here.
> Is it the gateway or the host that loses arp ?

On Linux, 'arp -an' is empty.  On Windows, I show the MAC of the gateway. 
Gateway is unable to ping either until the host pings either it or some 
other host on the same VLAN.


> 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.

It is - 'sh mac-addres vlan <x>' always shows it's there when I'm having the 
problem.



> 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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