[PLUG] A specific IP address not reachable via certain ISP

शंतनू shantanoo at gmail.com
Tue Dec 21 09:04:04 PST 2010


On 18-Nov-2010, at 8:11 PM, Mayuresh wrote:

> I find this strange. Can someone help?
> 
> I use Tata Indicom connection. The internet appears generally accessible
> but for a certain ip address : 59.163.6.13
> 
> I tried ping, which just hangs.
> 
> Traceroute shows 4 steps and then just stars.
> 
> I tried connection of another ISP and online ping tools: With these the
> server appears up and accessible fine.
> 
> Could the problem be with my machine's setup ? I think not. Could it be
> with routing info with some switch on the path? Anything else?

Section from 'man traceroute'

===
     A more interesting example is:

     [yak 72]% traceroute allspice.lcs.mit.edu.
     traceroute to allspice.lcs.mit.edu (18.26.0.115), 64 hops max
     1  helios.ee.lbl.gov (128.3.112.1)  0 ms  0 ms  0 ms
     2  lilac-dmc.Berkeley.EDU (128.32.216.1)  19 ms  19 ms  19 ms
     3  lilac-dmc.Berkeley.EDU (128.32.216.1)  39 ms  19 ms  19 ms
     4  ccngw-ner-cc.Berkeley.EDU (128.32.136.23)  19 ms  39 ms  39 ms
     5  ccn-nerif22.Berkeley.EDU (128.32.168.22)  20 ms  39 ms  39 ms
     6  128.32.197.4 (128.32.197.4)  59 ms  119 ms  39 ms
     7  131.119.2.5 (131.119.2.5)  59 ms  59 ms  39 ms
     8  129.140.70.13 (129.140.70.13)  80 ms  79 ms  99 ms
     9  129.140.71.6 (129.140.71.6)  139 ms  139 ms  159 ms
     10  129.140.81.7 (129.140.81.7)  199 ms  180 ms  300 ms
     11  129.140.72.17 (129.140.72.17)  300 ms  239 ms  239 ms
     12  * * *
     13  128.121.54.72 (128.121.54.72)  259 ms  499 ms  279 ms
     14  * * *
     15  * * *
     16  * * *
     17  * * *
     18  ALLSPICE.LCS.MIT.EDU (18.26.0.115)  339 ms  279 ms  279 ms

     Note that the gateways 12, 14, 15, 16 & 17 hops away either don't send ICMP "time exceeded" messages or send them with a ttl too small to reach
     us.  14 - 17 are running the MIT C Gateway code that doesn't send "time exceeded"s.  God only knows what's going on with 12.
===

Could be the one of the reason.


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