Traceroute explanation

Steven Bellovin smb at cs.columbia.edu
Thu Dec 8 15:33:09 CST 2011


On Dec 7, 2011, at 2:51 08PM, Meftah Tayeb wrote:

> big thank for that
> but, i am testing that for one day :)



Can you do an AStraceroute or manually translate those addresses into AS#s?  
That is, might level3 and tinet  be using multiple AS#s, in which case this
isn't unreasonable?





> 
> 
> ----- Original Message ----- From: "Fred Baker" <fred at cisco.com>
> To: "Meftah Tayeb" <tayeb.meftah at gmail.com>
> Cc: <nanog at nanog.org>
> Sent: Thursday, December 08, 2011 11:23 PM
> Subject: Re: Traceroute explanation
> 
> 
> 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
>> 
> 
> 
> 
> __________ Information from ESET NOD32 Antivirus, version of virus signature database 6695 (20111208) __________
> 
> The message was checked by ESET NOD32 Antivirus.
> 
> http://www.eset.com
> 
> 
> 
> 
> __________ Information from ESET NOD32 Antivirus, version of virus signature database 6695 (20111208) __________
> 
> The message was checked by ESET NOD32 Antivirus.
> 
> http://www.eset.com
> 
> 
> 
> 
> 


		--Steve Bellovin, https://www.cs.columbia.edu/~smb








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