[AusNOG] IOS router selection

[Chris Balmain]

Erm... meant to say ARP/ping reachability verification is *not* used 
unless you tell it to...

On 05/05/14 16:12, Chris Balmain wrote:
> The route is installed in the FIB if the router has a route to the 
> gateway itself (e.g. via a connected interface in up/up status, or 
> recursively via IGP etc)
>
> ARP/ping reachability verification is used unless you tell it to (on 
> Cisco via "ip sla" - 
> http://www.firewall.cx/cisco-technical-knowledgebase/cisco-routers/813-cisco-router-ipsla-basic.html)
>
> CB
>
> On 05/05/14 15:58, Alex Samad - Yieldbroker wrote:
>> Hi
>>
>> I am looking for some documentation that explains the way cisco behaves.
>>
>> If I have this
>>
>> IOS
>> ip route 0.0.0.0 0.0.0.0 w.x.y.z 230
>> ip route 0.0.0.0 0.0.0.0 f.g.h.i  240
>> ip route 0.0.0.0 0.0.0.0 r.s.t.u 250
>>
>> ASA
>> route internet 0.0.0.0 0.0.0.0 w.x.y.z 230
>> route internet 0.0.0.0 0.0.0.0 f.g.h.i 240
>> route internet 0.0.0.0 0.0.0.0 r.s.t.u 250
>>
>>
>> this tells me the default gateway used is w.x.y.z, unless that gateway is unavailable or dead..
>>
>> I am looking at how Cisco decides when a gateway is dead, I found documents on route selection, but nothing that specifically address dead gateways
>>
>> I presume, and from what I have seen if there is no arp its dead..
>>
>> Thanks
>> _______________________________________________
>> AusNOG mailing list
>> AusNOG at lists.ausnog.net
>> http://lists.ausnog.net/mailman/listinfo/ausnog
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ausnog.net/pipermail/ausnog/attachments/20140505/ff4c7df7/attachment.html>