[c-nsp] OSPF's handling of secondary IP addresses on subinterfaces

[Christopher J. Wargaski]

Hey Robert--

   Yep, been there and had the same problem with the secondary IP address
on an interface (physical or subinterface). When I discovered this, I
researched it and found that OSPF on IOS does not put the subnet for the
subinterface in the database.

   To get around that, you could probably a static route with next hop of
Null0 and tag then make a route map to advertise it.

cjw



Date: Fri, 6 Apr 2012 22:29:06 -0400
> From: Robert Johnson <fasterfourier at gmail.com>
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] OSPF's handling of secondary IP addresses on
>        subinterfaces
> Message-ID:
>        <CAOq=Mm=s8CQ1E+=HxNKqpdqohOP4w0fUdUTBiTG9eg7eWmr0LA at mail.gmail.com
> >
> Content-Type: text/plain; charset=ISO-8859-1
>
> I have a FastEthernet interface with multiple 802.1Q based
> subinterfaces. OSPF properly advertises routes for the subnets
> directly defined on these subinterfaces. However if I add secondary IP
> addresses to these subinterfaces, the subnets defined using the
> secondary command show up in the local routing table as directly
> connected, but OSPF doesn't advertise them to the rest of the area.
> The OSPF process includes network statements that encompass both
> primary and secondary IP addresses and they're all in the same area.
>
> Are there any limitations I should know about with OSPF on
> subinterfaces with secondary IP addresses?
>
> IOS 12.4(25) on a 3745.
>
> Thanks in advance.
>
>
>