Problem with Export Filter in OSPF

Ondrej Zajicek santiago at
Wed Oct 24 21:03:50 CEST 2012

On Wed, Oct 24, 2012 at 07:01:53PM +0200, Wendler, Daniel wrote:
> Hello,
> i'm new to bird and try to setup an OSPF Setup with 4 instances of bird on
> Linux Systems.
> The used version is 1.3.8 installed trough the Debian Squeeze Repo
> provided by
> At the moment i tried to establish an export filter for OSPF, and it
> seems, that it isn't working
> at all. Same filter works best as an import filter:
> filter notrans {
>         if net ~ [ ] then reject;
>         accept;
> }
> I want this net (and all subnets) not exported to other nodes in the OSPF
> Areas.
> I tried to test the filter on the system where i will export some routes.
>     via on eth1 [transospf 18:20] * IA
> (150/20) []    << this should not happen i think!
>   via on eth1 [transospf 18:20] ! IA

For OSPF, the export filter controls just the propagation of external
routes to OSPF. If some OSPF-claimed iface uses that prefix, OSPF will
propagate that regardless of filters. See this for similar question and
hints how to handle it:

Elen sila lumenn' omentielvo

Ondrej 'SanTiago' Zajicek (email: santiago at
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3,
"To err is human -- to blame it on a computer is even more so."
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