2 new GRH Tools: Which prefixes does my ASN miss? & Who misses my prefix?

Hank Nussbacher hank at efes.iucc.ac.il
Fri Jan 19 07:13:38 CET 2007

On Thu, 18 Jan 2007, Jeroen Massar wrote:

C00l t00l!  Is AT&T - AS5623 & AS7018 peering down since all /32s that I 
checked don't appear in their tables, yet you don't mark them down in 
italics as "Not seen at all by GRH, peering down?"


> Dear beloved Network Operators,
> I've just finished adding a nice tool for you to figure out which IPv6
> prefixes you are missing. It thus effectively shows you if you have
> misconfigured filters somewhere between you and the destination.
> This should keep you busy on your upcoming friday ;)
> First a special tool for ASN's having a working peering with GRH:
> "Which prefixes does my ASN miss?"
> Just go to the normal DFP page, and choose your ASN and which RIR you
> would like to take a look at, or all of them.
> See http://www.sixxs.net/tools/grh/dfp/ under the heading of "Missing
> DFP's per GRH participant" for this tool.
> I have to admit that there is a small bug in here though, that is if one
> or only a few ASN's do provide the route to GRH, GRH flags it as
> 'reachable', while actually it is not. This tool exposes that. I might
> later on change the behavior of GRH in itself so that it actually needs
> say, 50% of the GRH peers to carry the prefix before flagging the prefix
> as 'seen'. This is why for prefixes one is missing, you should check how
> many other ISP's see the prefix. That is why the "LG" link is present in
> every row.
> The second question "Who misses my prefix" can be answered by doing a
> Looking Glass query, eg using the normal query:
> http://www.sixxs.net/tools/grh/lg/?find=2610:78::/32
> One can also select to list all the non-GRH asns' which don't see the
> prefix. These ASN's are picked up from all the ASN paths in the total
> BGP tree and assuming that if they have one path, they should have the
> rest too.
> At the bottom, after the usual report, a report will form showing which
> ASN's are seen in the AS paths for that prefix. It lists additionally if
> those ASN's are peers of GRH. In the second part it will show a list of
> GRH peers that don't carry the prefix.
> Note that the 2610:78::/32 is seen/not seen 50/50. Thus clearly some
> people need to start updating their filters and kicking their upstreams.
> Enjoy your Fridays fixing them up :) *whistle*
> Greets,
> Jeroen
> PS: if you know a befriended (or enemy ;) ASN who is not peering yet
> with GRH, don't hesitate to point them to the signup URL and get them to
> participate, the more peers the better the quality of the data and the
> easier problems can be determined and fixed, the signup URL is at:
>  http://www.sixxs.net/tools/grh/signup/

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