Traceroute to ubuntuforums never finishes

[David Curtis]

gasell wrote:
>> Not really sure, after all you came pretty far. It would be more helpful
>> to see the times all the way from start.
>> Here is my trace:
>> //////////////////////////////////
>> carl at cfriisha:~$ sudo lft -D wlan0 feijoa.canonical.com
>>
>> Tracing ____________?_________?_______?_________?___.
>>
>> TTL  LFT trace to feijoa.canonical.com (91.189.94.12):80/tcp
>>  1   192.168.0.1 22.7ms
>>  2   217.197.58.33 126.6ms
>>  3   217.197.56.1 92.5ms
>> **   [neglected] no reply packets received from TTL 4
>>  5   te-X-Y.car2.copenhagen1.level3.net (4.68.111.17) 36.0/*/*ms
>> **   [neglected] no reply packets received from TTL 6
>>  7   ae-1-0.bbr1.London2.Level3.net (212.187.128.46) 69.2/*/*ms
>> **   [neglected] no reply packets received from TTLs 8 through 9
>> 10   gw0-0-gr.canonical.com (91.189.88.10) 65.8/*ms
>> **   [neglected] no reply packets received from TTLs 11 through 12
>> 13   [target] feijoa.canonical.com (91.189.94.12):80 73.1/*ms
>>
>> carl at cfriisha:~$
>> //////////////////////////////////
>>
>> This is a trace from Sweden.
>>
>> --
>>                           ---------=oOOo=---------
>>                             Carl Friis-Hansen
>>                             http://carl-fh.com/
>>                             Phone: +46 372 15033
>>                           ---------=oOOo=---------
> 
> Hm, using traceroute, it fails, but with lft it doesn't. Care to
> explain the difference?

Old traceroute uses the TTL (Time To Live) value [1]. Due to security 
concerns most gateways do not send an 'ICMP time exceded' back to the 
originator (you). So you end up with a 'No reply' or '***' for that hop. 
LFT (Layer Four Trace) uses SYN and FIN probes on top of TCP (ICMP is 
UDP) which does not get 'dropped' by gateways/routers between you and 
your target. [2]

> Then it might not be a networking issue at all. Yesterday I couldn't
> log in both with Firefox and Opera, today only Firefox refuses to
> work. Haven't had any strange issues with Firefox before :S.
> 

[1] http://en.wikipedia.org/wiki/Traceroute
[2] http://en.wikipedia.org/wiki/Layer_Four_Trace

Dave