Routes not deleted after link down

[Chuck Swiger]

Michal Vanco wrote:
> On Saturday 18 June 2005 20:48, Chuck Swiger wrote:
[ ... ]
>> Maybe.  If the system was not going to be reconnected to that network
>> anytime soon, it would be a good idea.  On the other hand, if the link down
>> was due to a transient failure of a wireless connection, which will be back
>> up in a second or two, it's much better not to drop the route and kill any
>> open connections.
> 
> hmm ... this approach is may be appropriate for deskop instalation. what about 
> internet router? shouldn't "fast convergence" be better in this case? imagine 
> two links connected to the same router with different metrics. if first of 
> them goes down, the second never gets used in this case.

You're right that a router should notice and quickly respond to an interface 
going down.  Routing software like routed, gated, zebra, CARP, freevrrpd should 
register to receive interface change notifications and do the appropriate 
thing.  In fact, that's pretty much what those programs actually do, although 
the details vary.

Anyway, if you don't run such programs, FreeBSD generally is using static 
routes or a simple dynamic default route discovered via DHCP.  The network 
stack has timeouts in place to close down open TCP connections and the like if 
no traffic can be sent for a long time.

-- 
-Chuck