In a message written on Mon, Jun 06, 2011 at 04:38:26PM +0200, Bjørn Mork wrote:
You can convince your traceroute to do that for you:
-A --as-path-lookups Perform AS path lookups in routing registries and print results directly after the corresponding addresses
I have not had good luck with that feature. Here's a FreeBSD traceroute, using the same host I referenced before: % traceroute -a efes.iucc.ac.il traceroute to efes.iucc.ac.il (128.139.202.17), 64 hops max, 52 byte packets 1 [AS1280] exit.blue.sql1.isc.org (149.20.48.1) 4.658 ms 2.718 ms 1.778 ms 2 [AS1280] int-0-4-0-0.r1.pao1.isc.org (149.20.65.9) 3.656 ms 2.363 ms 0.944 ms 3 [AS1221] ge-9-15-1G.ar1.PAO2.gblx.net (64.215.195.21) 50.539 ms 50.508 ms 59.709 ms 4 [AS3549] DANTE.TenGigabitEthernet7-3.ar1.FRA4.gblx.net (207.138.144.46) 166.476 ms 166.240 ms 166.243 ms 5 [AS20965] iucc-lb1-gw.rt1.fra.de.geant2.net (62.40.125.122) 230.590 ms 230.587 ms 230.545 ms 6 [AS378] gp1-gp0-te.ilan.net.il (128.139.188.1) 230.546 ms 230.579 ms 230.528 ms 7 * * * Now, I happen to administer hop #2, and know the packets are leaving on a link to Global Crossing (glbx.net). How AS 1221, which is Telstra, ends up in there is beyond me. From a Juniper box with a full table: bicknell@re0.r7.pao1> traceroute as-number-lookup efes.iucc.ac.il traceroute to efes.iucc.ac.il (128.139.202.17), 30 hops max, 40 byte packets 1 int-2-0-0.r1.pao1.isc.org (149.20.65.16) 4.448 ms 3.973 ms 3.222 ms 2 ge-9-15-1G.ar1.PAO2.gblx.net (64.215.195.21) 50.724 ms 67.135 ms 50.761 ms 3 DANTE.TenGigabitEthernet7-3.ar1.FRA4.gblx.net (207.138.144.46) [AS 3549] 159.652 ms 159.571 ms 160.003 ms 4 iucc-lb1-gw.rt1.fra.de.geant2.net (62.40.125.122) [AS 20965] 279.761 ms 275.059 ms 230.929 ms 5 gp1-gp0-te.ilan.net.il (128.139.188.1) [AS 378] 231.149 ms 231.222 ms 231.258 ms 6 * * * At least it's not wrong, but there is no ASN listed because the /30 on the link between 2 and 3 is internal, so it views hop 3 as being internal to my ASN, when it is not. But more importantly, not all traceroutes have this feature, and as I said it's about being polite. -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/