arp refresh rate

Gavin Atkinson gavin.atkinson at ury.york.ac.uk
Mon Dec 18 12:40:02 GMT 2006


On Mon, 2006-12-18 at 13:47 +0200, Peter Kirk wrote:
> Hi All
> 
> I have a bit of a problem.  We have a 6.1 FreeBSD server with natting
> and firewall rules for the servers behind it.  This FreeBSD server has
> an identical fail over server.
> 
> The other night we tested the fail over server.  It worked find but
> because the gateway before the fail over server had arp cache "the old
> Mac-addresses" it took about 5 minutes before we could access the
> servers behind the fail over server.
> 
> Is there anyway that you are able to set the arp cache refresh time?

Several ways:  Either use carp to manage the IP address and failover
(which ensures that if failover occurs, the MAC address moves with the
service), or after failover, send a gratuitous ARP packet or two to
servers that are caching the result - look at the net/arping port for
this.

Gavin




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