AS0 in AS path

Mikhail Strizhov strizhov at
Fri Aug 6 22:10:36 UTC 2010

  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.

Mikhail Strizhov
Email: strizhov at <mailto:strizhov at>

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. :)

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