Ospfd filtering

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Ospfd filtering

Pawel
Hello all,

I would like to ask, if it's possible to filter incoming and outgoing
announcements from neighbors in the same area (in the same way as in bgpd)?
If it isn't implemented, maybe somebody knows, if it will be possible in
future releases ospfd?
I'm using ospfd from OpenBSD 5.1.

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Re: Ospfd filtering

Stuart Henderson
On 2013-02-11, Pawel <[hidden email]> wrote:
> Hello all,
>
> I would like to ask, if it's possible to filter incoming and outgoing
> announcements from neighbors in the same area (in the same way as in bgpd)?
> If it isn't implemented, maybe somebody knows, if it will be possible in
> future releases ospfd?
> I'm using ospfd from OpenBSD 5.1.
>
>

It is not. All OSPF routers in an area *must* have a consistent view of
the area's database in order to carry out the SPF algorithm; filtering
announcements in the same way as BGP is incompatible with this.

Any filtering within an area would need to be done between receving
routes via OSPF and installing them in the kernel route table (RIB),
i.e. OSPF would still have the routes but not install some of them
to the kernel routing table - filtering would be local to the router
only. This is possible with some other OSPF implementations but I
didn't hear of any plans for doing this in ospfd.

http://blog.ine.com/2009/08/17/ospf-route-filtering-demystified/
has a bit more (but cisco-centric) information on this.