comcast routing problems

Frank DiPrete fdiprete at comcast.net
Sun Nov 1 11:58:59 EST 2009 

Yes, my router is returning a hop count exceeded.

There isn't much I can do about it. all of my traffic is sent to a dr 
assigned by dhcp. I have seen this sort of problem before when a router 
somewhere in the isp is configured incorrectly. Over-lapping other 
people's assigned IP address range is always a recipe for disaster.



my pub ip is 75.69.253.x/22

cisco-3600>show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
        D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
        N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
        E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
        i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS 
inter area
        * - candidate default, U - per-user static route, o - ODR
        P - periodic downloaded static route

Gateway of last resort is 75.69.252.1 to network 0.0.0.0

C    192.168.168.0/24 is directly connected, FastEthernet0/1
      75.0.0.0/22 is subnetted, 1 subnets
C       75.69.252.0 is directly connected, FastEthernet0/0
S*   0.0.0.0/0 [254/0] via 75.69.252.1


traceroute gets nothing back

cisco-3600>ping 75.69.252.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 75.69.252.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/8 ms
cisco-3600>traceroute 75.126.162.205

Type escape sequence to abort.
Tracing the route to 75.126.162.205

   1  *  *  *
   2  *  *  *
   3  *  *  *
   4  *  *  *
   5  *  *  *
   6  *  *  *
   7  *  *  *
   8  *  *  *
   9  *  *  *
  10  *  *  *

all the way to 30



Ben Scott wrote:
> On Sun, Nov 1, 2009 at 8:03 AM, Frank DiPrete <fdiprete at comcast.net> wrote:
>> My router is returning max hops exceeded.
> 
>   *Your* router is returning that?  If so, something's wrong on your
> router.  TTL (Time To Live) is a counter.  Every router hop, it gets
> decreased by one.  If it hits zero, that router sends a ICMP "Time
> Exceeded" message to the sender (you).
> 
>   The initial TTL is usually something like 64 or 128.  If *your*
> router is returning the Time Exceeded message, then TTL reached zero
> within your router.  That suggests a routing loop within your network,
> eating up TTL until it expires.
> 
>> I'm trying to figure out if it is a comcast problem, a qwest problem,
>> or a specific comcast problem after my super terrific speed upgrade.
> 
>   One of the first things you want to do is run a traceroute to the
> problem destination.  That will help give you an idea of what you can
> reach, and what you cannot.
> 
>> Any lucky people out there able to get to them?
> 
>   I opened the web site in my browser with no problem.  I'm in Dover,
> NH, on Comcast "home".  Here's my traceroute:
> 
> $ traceroute www.linuxquestions.org
> traceroute to www.linuxquestions.org (75.126.162.205), 30 hops max, 40
> byte packets
>  1  noid (10.10.10.1)  0.652 ms  1.572 ms  1.896 ms
>  2  73.194.244.1 (73.194.244.1)  9.164 ms  15.437 ms  20.242 ms
>  3  ge-1-2-ur01.dover.nh.boston.comcast.net (68.87.153.1)  21.782 ms
> 22.290 ms  22.711 ms
>  4  te-5-3-ur01.exeter.nh.boston.comcast.net (68.87.145.93)  21.179 ms
>  21.473 ms  21.572 ms
>  5  po-21-ur02.manchester.nh.boston.comcast.net (68.87.145.110)
> 23.165 ms  23.268 ms  23.644 ms
>  6  po-20-ur01.manchester.nh.boston.comcast.net (68.87.145.113)
> 22.715 ms  17.935 ms  18.142 ms
>  7  po-23-ur01.nashua.nh.boston.comcast.net (68.87.145.117)  18.533 ms
>  14.568 ms  14.257 ms
>  8  po-20-ur02.nashua.nh.boston.comcast.net (68.87.147.158)  12.604 ms
>  16.601 ms  16.529 ms
>  9  be-23-ar01.needham.ma.boston.comcast.net (68.87.145.245)  17.938
> ms  16.131 ms  11.333 ms
> 10  pos-0-1-0-0-ar01.chartford.ct.hartford.comcast.net (68.85.162.74)
> 19.468 ms  23.656 ms  23.889 ms
> 11  pos-2-5-0-0-cr01.newyork.ny.ibone.comcast.net (68.86.90.65)
> 26.824 ms  27.093 ms  27.195 ms
> 12  pos-1-14-0-0-cr01.mclean.va.ibone.comcast.net (68.86.85.93)
> 32.442 ms  32.708 ms  32.802 ms
> 13  pos-1-10-0-0-cr01.atlanta.ga.ibone.comcast.net (68.86.86.126)
> 54.132 ms  54.401 ms  54.498 ms
> 14  pos-1-10-0-0-cr01.dallas.tx.ibone.comcast.net (68.86.86.129)
> 75.541 ms  75.775 ms  79.325 ms
> 15  softlayer-cr01.dallas.tx.ibone.comcast.net (75.149.228.34)  76.229
> ms  71.623 ms  73.463 ms
> 16  po2.dar02.dal01.dallas-datacenter.com (66.228.118.207)  77.679 ms
> 76.604 ms  76.666 ms
> 17  po2.fcr02.dal01.dallas-datacenter.com (66.228.118.182)  76.088 ms
> 73.631 ms  79.129 ms
> 18  www.linuxquestions.org (75.126.162.205)  78.850 ms  71.065 ms  74.596 ms
> $
> 
>   For comparison, here's the traceroute from a "Comcast Workplace"
> feed in Amesbury, MA:
> 
> arcgate$ traceroute www.linuxquestions.org
> traceroute to www.linuxquestions.org (75.126.162.205), 30 hops max, 40
> byte packets
>  1  73.168.168.1 (73.168.168.1)  6.075 ms  11.455 ms  11.467 ms
>  2  68.85.186.81 (68.85.186.81)  11.546 ms  11.532 ms  11.592 ms
>  3  te-9-1-ur01.kingston.nh.boston.comcast.net (68.87.146.181)  11.613
> ms  11.646 ms  11.665 ms
>  4  te-8-1-ur02.londonderry.nh.boston.comcast.net (68.87.146.177)
> 12.051 ms  12.110 ms  12.137 ms
>  5  te-9-1-ur01.londonderry.nh.boston.comcast.net (68.87.146.169)
> 11.664 ms  16.081 ms  16.150 ms
>  6  te-0-9-0-4-ar01.needham.ma.boston.comcast.net (68.87.146.194)
> 16.212 ms  13.956 ms  13.290 ms
>  7  pos-0-1-0-0-ar01.chartford.ct.hartford.comcast.net (68.85.162.74)
> 16.065 ms  15.157 ms  15.204 ms
>  8  pos-2-3-0-0-cr01.newyork.ny.ibone.comcast.net (68.86.90.57)
> 18.076 ms  18.395 ms  22.310 ms
>  9  pos-1-12-0-0-cr01.mclean.va.ibone.comcast.net (68.86.85.29)
> 28.228 ms  28.249 ms  28.273 ms
> 10  pos-1-15-0-0-cr01.atlanta.ga.ibone.comcast.net (68.86.85.69)
> 54.302 ms  54.330 ms  55.442 ms
> 11  pos-1-11-0-0-cr01.dallas.tx.ibone.comcast.net (68.86.85.221)
> 76.730 ms  77.890 ms  74.356 ms
> 12  softlayer-cr01.dallas.tx.ibone.comcast.net (75.149.228.34)  73.023
> ms  74.074 ms  74.011 ms
> 13  po2.dar02.dal01.dallas-datacenter.com (66.228.118.207)  73.878 ms
> 74.590 ms  74.489 ms
> 14  po2.fcr02.dal01.dallas-datacenter.com (66.228.118.182)  74.626 ms
> 97.208 ms  97.056 ms
> 15  www.linuxquestions.org (75.126.162.205)  72.118 ms  74.035 ms  74.038 ms
> arcgate$
> 
> -- Ben
> _______________________________________________
> gnhlug-discuss mailing list
> gnhlug-discuss at mail.gnhlug.org
> http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
> 
>

More information about the gnhlug-discuss mailing list