Can't access certain domains - what can I do, or ask my ISP to do?

Question

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?

Answer 1

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