Thanks everyone. Answer is simple - 4byte ASN's. I was parsing Route Views RIB-IN tables, and found that, by default, Quagga is using 4byte AS length field to store 2-byte and 4-byte AS Numbers. So, using 2 bytes length in parser, I had wierd output like "0 3549 0 1239" and so on. -- Sincerely, Mikhail Strizhov Email: strizhov@cs.colostate.edu <mailto:strizhov@cs.colostate.edu> On 08/06/2010 03:47 PM, Kameron Gasso wrote:

On 08/06/2010 02:15 PM, Mikhail Strizhov wrote:

...

Does anybody have\had experience with BGP announces containing AS 0 in AS path? I know that AS 0 is reserved by IANA, but still, is it possible to receive such announce messages? eBGP or iBGP? What type of device and/or software are you using to speak BGP?

As far as I know, most devices should NOT let you set your ASN to 0 or let you add it to the AS path.

My guess is it's probably going to be filtered by the BGP scanner, but I don't have any gear laying around that I can play with at the moment to confirm. :)

On Aug 6, 2010, at 11:48 AM, Valdis.Kletnieks@vt.edu wrote:

On Fri, 06 Aug 2010 15:15:47 MDT, Mikhail Strizhov said:

...

Does anybody have\had experience with BGP announces containing AS 0 in AS path? I know that AS 0 is reserved by IANA, but still, is it possible to receive such announce messages?

After 3 decades in this business, I can make two predictions:

1) Somebody has managed to fat-finger something and announced AS0 at some point.

2) At least one vendor's gear promptly committed seppuku *after* passing the broken announcement on to its neighbors.

Those aren't predictions, they're statistically certain observations. :-) Regards, -drc