Connection timed out when connecting to a website (ubuntu only)

Question

I've been struggling with these problem for months. It happens randomly and it happens on Ubuntu only (12.04). It's about my hosted company website.

Some facts:

I can ping it
I can traceroute it
I can dig it
I can make a nslookup

But whenever I try to open it in Chrome it won't open. I also tried using polipo but got same connection time out issue.

I'm connected through a LAN network and I'm experiencing no problem with any other website.

Is there a more accurate debugging technique I'm missing other than pinging/tracerouting, etc.?

can you put the steps as an answer so future visitors know how to solve it? — Alvar, Jun 27 '13 at 10:44
Here are several answers on Ask Ubuntu explaining it: http://askubuntu.com/questions/201185/tor-and-polipo-installation-steps — S.C., Jul 01 '13 at 12:27

score 3 · Answer 1 · edited Jun 27 '13 at 09:58

Run tcpdump using something like this:

tcpdump -nieth0 -s0 -w/tmp/dump.pcap port 80 or icmp

or if you are not logged in as root

    sudo tcpdump -nieth0 -s0 -w/tmp/dump.pcap port 80 or icmp

Attempt to access the website.
Press Ctrl+C on tcpdump and then use the wireshark program to examine the capture file (/tmp/dump.pcap). You can find Wireshark in the software centre.
Do the same for a website that does work, and look for relevant differences.
Do the same but at the hosting end.

Robie Basak · Answer 2 · 2013-06-27T09:14:06.260

1

Eliminate an MTU problem by pinging with increasingly large packets using ping's -s option, all the way up to 1492. If it turns out that large pings don't work, then something along your path cannot handle 1500-byte packets but is blocking the fragmentation needed packets from coming back.

edited Jun 27 '13 at 09:14

answered Jun 27 '13 at 09:08

Robie Basak

15,670

1

Alternatively the tracepath command might help automating this process. – lgarzo Jun 27 '13 at 09:11

Connection timed out when connecting to a website (ubuntu only)

2 Answers2