nanog mailing list archives

Re: Traceroute explanation


From: "Harsha V. Madhyastha" <harsha () cs ucr edu>
Date: Thu, 8 Dec 2011 13:37:11 -0800

Another explanation could be load balancing. As Fred mentioned, traceroute sends out different packets for different 
hops on the path and since these packets have different headers, load balancers on the path may hash packets with 
different TTL values on to different paths.

Check out http://www.paris-traceroute.net/ for more information.

--Harsha

On Dec 8, 2011, at 1:23 PM, Fred Baker wrote:

This is just a guess, but I'll bet the route changed while you were measuring it.

Traceroute sends a request, awaits a response, sends a request, ... Suppose that the route was

172.28.0.1 -> 10.16.0.2
          -> 41.200.16.1
          -> 172.17.2.25
          -> 213.140.58.10
          -> 195.22.195.125
          -> 4.69.151.13
          -> 213.200.68.61
          -> somewhere else

and after the test got that far, two systems got inserted into the path before level3, resulting in the route 
entering level3 at a different point, 4.69.141.249. What you now have is

172.28.0.1 -> 10.16.0.2
          -> 41.200.16.1
          -> 172.17.2.25
          -> 213.140.58.10
          -> 195.22.195.125
          -> unknown
          -> unknown
          -> 4.69.141.249
          -> 77.67.66.154
          -> and so on

The effect would be to get a result like this.

Next time you see something like this, suggestion: repeat the traceroute and see what you get.


On Dec 7, 2011, at 12:12 PM, Meftah Tayeb wrote:

Hey folks,
i see a strange traceroute there

Détermination de l'itinéraire vers www.rri.ro [193.231.72.52]
avec un maximum de 30 sauts :

1     2 ms     1 ms     1 ms  172.28.0.1
2     1 ms     1 ms     1 ms  localhost [10.16.0.2]
3    10 ms    10 ms    13 ms  41.200.16.1
4    11 ms    10 ms    11 ms  172.17.2.25
5    21 ms    21 ms    21 ms  213.140.58.10
6    34 ms    31 ms    55 ms  pos14-0.palermo9.pal.seabone.net [195.22.197.125
]
7    34 ms    33 ms    35 ms  ae-5-6.bar2.marseille1.level3.net [4.69.151.13]
8   106 ms    68 ms    67 ms  xe-1-1-0.mil10.ip4.tinet.net [213.200.68.61]
9    74 ms    73 ms    74 ms  ae-1-12.bar1.budapest1.level3.net [4.69.141.249]
10    63 ms    63 ms    79 ms  euroweb-gw.ip4.tinet.net [77.67.66.154]
11    85 ms    84 ms    84 ms  v15-core1.stsisp.ro [193.151.28.1]
12   100 ms   100 ms   102 ms  inet-crli1.qrli1.buh.ew.ro [81.24.28.226]
13    81 ms    81 ms    81 ms  193.231.72.10
14    92 ms    92 ms    93 ms  ip4-89-238-225-90.euroweb.ro [89.238.225.90]
15    89 ms    89 ms    89 ms  webrri.rri.ro.72.231.193.in-addr.arpa [193.231.7
2.52]
Itinéraire déterminé.
C:\Documents and Settings\TAYEB>
Seabone, then level3, then Tinet, then level3, then tinet ?
if is that a routing stufs that i don't know, please let me know :)
i never saw that befaure

  Meftah Tayeb
IT Consulting
http://www.tmvoip.com/ 
phone: +21321656139
Mobile: +213660347746


__________ Information from ESET NOD32 Antivirus, version of virus signature database 6695 (20111208) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com






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