Google and IPv6 inverse?

Leo Bicknell bicknell at ufp.org
Mon Jun 6 14:49:41 UTC 2011


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 at 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 at ufp.org - CCIE 3440
        PGP keys at http://www.ufp.org/~bicknell/
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