Newbie question - create filter for prefixes to export and also modify bgp next hop
Mathias Wolkert
tias at netnod.se
Wed Mar 2 14:55:53 CET 2011
Hi
On 3/2/11 11:32 , Ondrej Filip wrote:
> On 2.3.2011 10:36, Mathias Wolkert wrote:
>> Hi
>>
>> As said, I'm new to BIRD and struggling a bit with the config syntax.
>>
>> I'll try to explain what I want to do.
>>
>> I have a few prefixes, lets say 10.1.1.0/24, 10.2.2.0/24, 10.3.3.0/24.
>> I want to announce these (and only these) in a BGP session, but with a
>> modified next hop.
>>
>> How would I do this?
>
> Add this export filter to you BGP session:
>
> export filter {
> if net ~ [10.1.1.0/24, 10.2.2.0/24, 10.3.3.0/24] then {
> bgp_next_hop = X.X.X.X;
> accept;
> }
> else reject;
> };
>
> (I did not check syntax, maybe some ';' is missing.
> Ondrej
Working fine, thanks a lot.
Now say I want to do this for all my +100 peers could I do the filtering
once in a filter and call that in every session?
Another thing.
One of these prefixes I want to originate from a different AS.
In IOS and quagga I can do this with "set as-path prepend" and get:
prefix/mask <local_as> <prepended_as> i
Doing this in BIRD gives me a different behavior and I get:
prefix/mask <prepended_as> <local_as> i
A little bird told me about this not beeing wrong, but closer to what
the standard states.
Do you agree?
How would I get around this, another table and pipes?
/Tias
>
>
>>
>> Any help is much appreciated.
>>
>> /Tias
>
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