BGP Community - AS0 is de-facto "no-export-to" marker - Any ASN reserved to "export-only-to"?'

Arnold Nipper arnold at
Tue Sep 8 22:12:40 UTC 2020


On 08.09.2020 17:55, Douglas Fischer via NANOG wrote:
> Most of us have already used some BGP community policy to no-export some
> routes to some where.
> On the majority of IXPs, and most of the Transit Providers, the very
> common community tell to route-servers and routers "Please do no-export
> these routes to that ASN" is:
>  -> 0:<TargetASN>
> So we could say that this is a de-facto standard.
> But the Policy equivalent to "Please, export these routes only to that
> ASN" is very varied on all the IXPs or Transit Providers.
> With that said, now comes some questions:
> 1 - Beyond being a de-facto standard, there is any RFC, Public Policy,
> or something like that, that would define 0:<TargetASN> as
> "no-export-to" standard?
> 2 - What about reserving some 16-bits ASN to use <ExpOnlyTo>:<TargetASN>
> as "export-only-to" standard?
> 2.1 - Is important to be 16 bits, because with (RT) extended
> communities, any ASN on the planet could be the target of that policy.
> 2.2 - Would be interesting some mnemonic number like 1000 / 10000 or so.

you may want to have a look at

Keep calm, keep distance, keep connected!

Arnold Nipper
email: arnold at
mobile: +49 172 2650958

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 261 bytes
Desc: OpenPGP digital signature
URL: <>

More information about the NANOG mailing list