Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I've had intermittent failures trying to establish connections to anything on the colorado.edu domain. Existing connections stayed open, but I couldn't establish any new ones - neither ssh nor http.

This traceroute shows about 5 minutes of failing to establish a connection, followed by success (after which everything turned OK again...):

traceroute to www.colorado.edu (128.138.129.98), 64 hops max, 72 byte packets
 1  192.168.1.1 (192.168.1.1)  1.027 ms  36.564 ms  3.478 ms
 2  67.164.172.1 (67.164.172.1)  65.141 ms  49.820 ms  25.116 ms
 3  te-7-3-ur01.boulder.co.denver.comcast.net (68.85.220.65)  20.845 ms  12.437 ms  14.861 ms
 4  te-0-11-0-6-ar02.denver.co.denver.comcast.net (68.86.103.157)  45.525 ms  39.944 ms  31.850 ms
 5  te-4-1-ur01.denver.co.denver.comcast.net (68.86.179.226)  17.874 ms  49.199 ms  19.179 ms
 6  68.86.128.18 (68.86.128.18)  13.251 ms  15.289 ms  12.767 ms
 7  * * *
 8  * * *
 9  * * *
10  * * *
11  * * *
12  * * *
13  * * *
14  * * *
15  * * *
16  * * *
17  * * *
18  * * *
19  * * *
20  * * *
21  * * *
22  * * *
23  * * *
24  * * *
25  * * *
26  * * *
27  * * *
28  * * *
29  * * *
30  * * *
31  * * *
32  * * *
33  * * *
34  www.colorado.edu (128.138.129.98)  13.781 ms  39.796 ms  32.182 ms

I was able to access the site from my phone, which clearly took a different route, so there's no problem with the Colorado servers. What could cause this? Is there any workaround? If there's nothing I can do directly, is there anything I can ask my ISP to do?

share|improve this question
    
DNS isn't the problem; lookups were still getting me the right IP. –  keflavich Dec 10 '12 at 6:24

1 Answer 1

up vote 1 down vote accepted

Comcast has a routing problem. If you want to circumvent their routing issue you can TRY using a VPN service. By entering a VPN tunnel you will exit at another point and not have to worry about Comcast's routing. However, this is a work around. You should call them, tell them they have a routing issue, and you can provide a traceroute that shows there is a problem inside their network.

What a traceroute I snapped in Highlands Ranch through Century link looks like:

 1  10.0.0.1 (10.0.0.1)  1.499 ms  1.827 ms  1.117 ms
 2  hlrn-dsl-gw05.hlrn.qwest.net (207.225.112.5)  21.003 ms  20.886 ms  32.002 ms
 3  hlrn-agw1.inet.qwest.net (71.217.188.33)  27.487 ms  21.190 ms  25.492 ms
 4  dvr-brdr-02.inet.qwest.net (67.14.24.118)  21.287 ms  20.440 ms  22.168 ms
 5  den-b1-link.telia.net (213.248.102.185)  24.164 ms  23.860 ms  78.980 ms
 6  lambdarail-ic-145002-den-b1.c.telia.net (213.248.78.206)  21.791 ms  21.797 ms  23.052 ms
 7  xe-1-3-0.core-1200.frgp.net (192.43.217.169)  20.041 ms  21.560 ms  22.814 ms
 8  ucb-i1-frgp.colorado.edu (198.59.55.9)  24.435 ms  23.404 ms  23.678 ms
 9  hut-juniper.colorado.edu (128.138.81.249)  24.814 ms  23.189 ms  24.516 ms
10  its-hut.colorado.edu (128.138.81.9)  23.163 ms  23.255 ms  26.577 ms
11  www.colorado.edu (128.138.129.98)  23.658 ms  26.457 ms  23.534 ms
share|improve this answer
    
Thanks. How do you get in touch with someone at an ISP who will understand what's going on? Comcast, at least, has a mile-thick wall to make sure you've plugged in your router before you can talk to a person... –  keflavich Dec 10 '12 at 16:11

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.