Is there an issue to be fixed when traceroute consistently prints a line with "6 * * *"?

Question

I am trying to figure out why I am having trouble reaching a particular website from my Mac OSX Yosemite. The service provider suggested that I run a traceroute, when I do, regardless of the destination, I get a result like this:

traceroute to google.com (74.125.239.96), 64 hops max, 52 byte packets
 1  10.1.10.1 (10.1.10.1) 60 bytes to 10.1.10.14  1.398 ms  1.423 ms  1.202 ms
 2  24.4.6.1 (24.4.6.1) 36 bytes to 10.1.10.14  11.383 ms  9.741 ms  9.311 ms
 3  te-0-2-0-12-sur04.santaclara.ca.sfba.comcast.net (162.151.30.169) 76 bytes to 10.1.10.14  9.483 ms  10.148 ms  9.452 ms
 4  te-0-5-0-8-sur03.santaclara.ca.sfba.comcast.net (162.151.78.109) 76 bytes to 10.1.10.14  9.690 ms
    te-0-5-0-9-sur03.santaclara.ca.sfba.comcast.net (162.151.78.113) 76 bytes to 10.1.10.14  9.923 ms
    te-0-5-0-2-sur03.santaclara.ca.sfba.comcast.net (69.139.198.41) 76 bytes to 10.1.10.14  10.323 ms
 5  be-232-ar01.santaclara.ca.sfba.comcast.net (162.151.78.253) 76 bytes to 10.1.10.14  12.258 ms  13.268 ms  9.708 ms
 6  * * *
 7  he-0-10-0-0-pe03.11greatoaks.ca.ibone.comcast.net (68.86.85.214) 76 bytes to 10.1.10.14  15.528 ms
    he-0-13-0-0-pe03.11greatoaks.ca.ibone.comcast.net (68.86.83.134) 76 bytes to 10.1.10.14  11.379 ms
    he-0-15-0-1-pe03.11greatoaks.ca.ibone.comcast.net (68.86.86.222) 76 bytes to 10.1.10.14  11.174 ms
 8  173.167.59.66 (173.167.59.66) 36 bytes to 10.1.10.14  14.655 ms
    66-208-228-70.ubr01a.hurtl301.al.hfc.comcastbusiness.net (66.208.228.70) 36 bytes to 10.1.10.14  10.514 ms
    173.167.59.66 (173.167.59.66) 36 bytes to 10.1.10.14  35.888 ms
 9  72.14.232.138 (72.14.232.138) 36 bytes to 10.1.10.14  10.164 ms
    209.85.241.55 (209.85.241.55) 36 bytes to 10.1.10.14  13.837 ms  15.349 ms
10  66.249.95.29 (66.249.95.29) 36 bytes to 10.1.10.14  13.930 ms  10.773 ms  15.731 ms
11  nuq05s01-in-f0.1e100.net (74.125.239.96) 60 bytes to 10.1.10.14  12.693 ms  16.125 ms  11.041 ms

Notice on step 6, the three asterisks (*), when these are printing, it is very slow, each one takes about four seconds to appear. According to the man page:

If there is no response within a 5 sec. timeout interval (changed with the -w flag), a "*" is printed for that probe.

Why isn't there a name for the probe on line 6, or is that just line 7? I've noticed a similar result from another Comcast service provided location. Should I be talking to Comcast instead, and if so, what would I be asking them to fix? Would this issue be indicative of access to a particular website failing to work correctly? In addition to having periodic issues reaching the website mentioned at the top, I also have periodic issues with a VNC session to a completely unrelated system having 3 to 4 second timeouts where the screen is not being refreshed. Running a traceroute, I found a similar issue for that destination. I've been seeing these issues on and off for several months, but traceroute is consistently giving the timeouts.

Answer 1

No, there is nothing to fix as regards your traceroute.

First, the only devices on that list that are NOT routers are the first and the last. Every hop represents a router. Some of these routers may not be in public address space, in which case they couldn't display a name for the hop. Since you have hops after hop 6, this cannot be contributing to any problems you are having reaching a specific server.

Second, this has no relation to your VNC quality, or any other service, other than that they share a timeout interval. Traceroute does not test the quality of a connection at all, only its connectivity. There is no indication that actual traffic passing through the device at hop 6 would time out. Traceroute is a purely diagnostic thing, and is handled differently by routers than normal traffic like retrieving a webpage or sending packets in a VNC connection.

Specifically, the operator of the device at hop 6 has choosen not to send ICMP TTL Exceeded messages when a packet is dropped due to TTL (or perhaps it is not accepting ICMP PING/ECHO requests at all). Either way, it's someone elses device and it's their right to run it however they like. If the router does not respond with a TTL Exceeded message, traceroute will not print its name or IP.

If it helps, most people can't get as much info as you get between yourself and Google. I can only see about 3 hops between myself and them. all the rest of the hops time out.

Answer 2

A tip that might help analyse the problem to a deeper level.

I hope it is possible to get/create a working MAC-incarnation of mtr:
http://www.bitwizard.nl/mtr/

What is MTR?

mtr combines the functionality of the 'traceroute' and 'ping' programs in a single network diagnostic tool.

As mtr starts, it investigates the network connection between the host mtr runs on and a user-specified destination host. After it determines the address of each network hop between the machines, it sends a sequence ICMP ECHO requests to each one to determine the quality of the link to each machine. As it does this, it prints running statistics about each machine. For a preview take a look at the screenshots.

mtr is distributed under the GNU General Public License. See the COPYING file for details.