From: Scott Morris (swm@emanon.com)
Date: Mon Feb 06 2006 - 15:29:52 GMT-3
While the peer is obviously directly connected, it would not be considered a
directly connected peer route IMHO. Because it belongs to someone else two
hops away.
In the original example we're looking at, it asked for next AS or one hop
away. While technically, the route WOULD be on the 2nd AS back, it would
not fall within the regexp parameters since after the second AS listed, it
was expecting a $ (end of string) and if the 2nd AS prepended, then it would
not be the end of string but another entry.
Scott
-----Original Message-----
From: Jason Sinclair [mailto:jason_sinclair@pacific.net.au]
Sent: Sunday, February 05, 2006 9:11 PM
To: Scott Morris; Henk de Tombe; Nadeem Zahid (iszahid); Geert Nijs;
ccielab@groupstudy.com
Subject: RE: BGP Filter Question
Interestingly - would you consider a path such as 703 1221 1221 1221 as
directly connected?...............
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Scott Morris
Sent: Saturday, 4 February 2006 3:53 AM
To: 'Henk de Tombe'; 'Nadeem Zahid (iszahid)'; 'Geert Nijs';
ccielab@groupstudy.com
Subject: RE: BGP Filter Question
You can go to www.traceroute.org to find many of them, or search google for
"lookingglass bgp"
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Henk
de Tombe
Sent: Friday, February 03, 2006 2:28 AM
To: 'Nadeem Zahid (iszahid)'; Geert Nijs; ccielab@groupstudy.com
Subject: RE: BGP Filter Question
Hi,
You can telnet to a route server and play around with it by using the regexp
feature under show ip bgp:
route-server.phx1>sh ip bgp regexp ^701_ <------------------------------ BGP
table version is 46178201, local router ID is 67.17.81.28 Status codes:
s
suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i3.0.0.0 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
*>i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i 67.17.64.89 600 200 0 701 703 80
i
* i6.1.0.0/16 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
route-server.phx1>sh ip bgp regexp ^701_([0-9]+)?$ <-------------------- BGP
table version is 46177896, local router ID is 67.17.81.28 Status codes:
s
suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i6.1.0.0/16 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
*>i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i6.2.0.0/22 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
* i 67.17.64.89 600 200 0 701 668 i
Output omitted (lot's of spacebar entries later :-)
* i 67.17.64.89 600 200 0 701 26764 i
* i 67.17.64.89 600 200 0 701 26764 i
* i 67.17.64.89 600 200 0 701 26764 i
* i12.26.86.0/24 67.17.64.89 600 200 0 701 13758 i
* i 67.17.64.89 600 200 0 701 13758 i
* i 67.17.64.89 600 200 0 701 13758 i
* i 67.17.64.89 600 200 0 701 13758 i
* i12.26.117.0/24 67.17.64.89 600 200 0 701 i
* i 67.17.64.89 600 200 0 701 i
* i 67.17.64.89 600 200 0 701 i
* i 67.17.64.89 600 200 0 701 i
* i 67.17.64.89 600 200 0 701 i
* i 67.17.64.89 600 200 0 701 i
*>i 67.17.64.89 600 200 0 701 i
* i 67.17.64.89 600 200 0 701 i
* i 67.17.64.89 600 200 0 701 i
Here is a list of route-servers that Brian Dennis posted some while ago,
can't find the post anymore, but here they are:
route-server.gblx.net <---- this is the one I used.
route-server.savvis.net
route-server.colt.net
route-server.opentransit.net
route-server.gt.ca
route-server.belwue.de
Regards,
Henk
-----Oorspronkelijk bericht-----
Van: nobody@groupstudy.com [mailto:nobody@groupstudy.com] Namens Nadeem
Zahid (iszahid)
Verzonden: vrijdag 3 februari 2006 02:18
Aan: Geert Nijs; ccielab@groupstudy.com
Onderwerp: RE: BGP Filter Question
I think regexp should be: ^254(_[0-9]+)?$
-----Original Message-----
From: Geert Nijs [mailto:geert.nijs@simac.be]
Sent: Thursday, February 02, 2006 1:09 PM
To: Nadeem Zahid (iszahid); ccielab@groupstudy.com
Subject: RE: BGP Filter Question
Directly connected is just with one AS extra
so indeed
AS= 254 and any single number
If i remember correctly it should be something like:
^254_([0-9]*)$
correct me if i am wrong
Geert
CCIE #13729
-----Oorspronkelijk bericht-----
Van: nobody@groupstudy.com [mailto:nobody@groupstudy.com] Namens Nadeem
Zahid (iszahid)
Verzonden: donderdag 2 februari 2006 20:15
Aan: ccielab@groupstudy.com
Onderwerp: BGP Filter Question
What is considered "directly connected customer" in case of BGP?
Let say R1 is receiving some prefixes from 2 nbrs:
1.1.1.1 AS path= 254 100 200 300
2.2.2.2 AS path= 254 50
Let say we wanna only allow AS 254 and its directly connected customers
- does it mean that it should
be only 1 AS behind 254 (like 1 hop)?
I see examples permitting ^254(_[0-9])*$ which is not correct IMO as it will
allow any numbers of ASs behind 254.
Nadeem
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