Explain a difference between filters??

[Владислав Гришин]

Many thanks!

Vladislav grishin


-----Original Message-----
From: owner-bird-users at atrey.karlin.mff.cuni.cz
[mailto:owner-bird-users at atrey.karlin.mff.cuni.cz] On Behalf Of Ondrej Filip
Sent: Wednesday, July 07, 2010 11:49 PM
To: Vladislav grishin
Cc: bird-users at trubka.network.cz
Subject: Re: Explain a difference between filters??

On 7.7.2010 16:00, Vladislav grishin wrote:
>
> Why filters export_net_1 and export_net_2 work equally, and/but filters
> export_default_1 and export_default_1 on a miscellaneous?
> Why the filter export_default_2 "does not work" also as the filter
> export_net_2 works?

Hi Vladislav,

this clause:
net ~ 1.0.0.0/8
means "NET is subnetwork (of network itself) of 1.0.0.0/8". So 
networks like 1.1.0.0/16 or 1.0.0.0/8 are accepted by the filter.

But this clause:
net ~ [ 1.0.0.0/8 ]
means "NET is a member of prefix list (prefix list is in []) with a 
single member 1.0.0.0/8. So basically only 1.0.0.0/8 is matched.

That's why export_default_1 accepts just default route (0.0.0.0/0) and 
export_default_2 accepts default route and all subnetworks.

So your filters export_net_1 and export_net_2 are not equal. The 
filter export_net_2 would e.g. accept route 12.12.12.13/32, but that 
is probably not in your routing table.

"net ~ [ 1.0.0.0/8]" is equal with "net = 1.0.0.0/8"

			Ondrej F.



>
> Vladislav Grishin
>