LFT (Layer Four Traceroute)

lft is a variant of traceroute that uses per default TCP and port 80 to go through packet-filter based firewalls.

Example

142:/home/andreu# lft -d 80 -m 1 -M 3 -a 5 -c 20 -t 1000 -H 30 -s 53 www.cisco.com     
Tracing _________________________________.
TTL  LFT trace to www.cisco.com (198.133.219.25):80/tcp
1   129.renater.fr (193.49.159.129) 0.5ms
2   gw1-renater.renater.fr (193.49.159.249) 0.4ms
3   nri-a-g13-0-50.cssi.renater.fr (193.51.182.6) 1.0ms
4   193.51.185.1 0.6ms
5   PO11-0.pascr1.Paris.opentransit.net (193.251.241.97) 7.0ms
6   level3-1.GW.opentransit.net (193.251.240.214) 0.8ms
7   ae-0-17.mp1.Paris1.Level3.net (212.73.240.97) 1.1ms
8   so-1-0-0.bbr2.London2.Level3.net (212.187.128.42) 10.6ms
9   as-0-0.bbr1.NewYork1.Level3.net (4.68.128.106) 72.1ms
10   as-0-0.bbr1.SanJose1.Level3.net (64.159.1.133) 158.7ms
11   ge-7-0.ipcolo1.SanJose1.Level3.net (4.68.123.9) 159.2ms
12   p1-0.cisco.bbnplanet.net (4.0.26.14) 159.4ms
13   sjck-dmzbb-gw1.cisco.com (128.107.239.9) 159.0ms
14   sjck-dmzdc-gw2.cisco.com (128.107.224.77) 159.1ms
15   [target] www.cisco.com (198.133.219.25):80 159.2ms

References

• Home page: http://pwhois.org/lft/
• Debian package: lft - display the route packets take to a network host/socket

-- FrancoisXavierAndreu & SimonMuyal - 06 Jun 2005
-- SimonLeinen - 21 May 2006