Tracert (Trace Route)



In 1988, five years after the creation of "ping," Van Jacobson decided to modify the TTL field on the ping and use a backdoor (get an error response from a router by sending a 0 TTL packet) to create tracert. Where ping tests connectivity, tracert determines the problematic node (router).

Here is an example of a tracert session on a windows 2000 server to one of my favorite web sites, About North Georgia

C:\>tracert ngeorgia.com

Tracing route to ngeorgia.com [66.40.224.56]
over a maximum of 30 hops:

1 <10 ms <10 ms <10 ms 128.2.0.13
2 10 ms <10 ms <10 ms 65.160.124.113
3 30 ms 20 ms 20 ms sl-gw23-rly-8-5-TS25.sprintlink.net [160.81.67.169]
4 20 ms 20 ms 20 ms sl-bb21-rly-3-2.sprintlink.net [144.232.14.77]
5 20 ms 20 ms 20 ms sl-bb23-rly-11-0.sprintlink.net [144.232.14.134]
6 20 ms 20 ms 20 ms sl-gw19-rly-10-0.sprintlink.net [144.232.14.42]
7 20 ms 20 ms 30 ms sl-abovenet-27-0.sprintlink.net [144.223.41.218]
8 80 ms 90 ms 90 ms so-3-0-0.mpr3.sjc2.us.mfnx.net [208.184.233.133]
9 90 ms 81 ms 120 ms pos1-0.mpr1.pao1.us.above.net [209.249.0.121]
10 91 ms 90 ms 90 ms giga-abovenet.hostcentric.com [64.124.50.164]
11 90 ms 90 ms 90 ms host189.hostcentric.com [209.25.214.189]
12 90 ms 90 ms 90 ms VLAN5.FMT6509-1.hostcentric.com [66.40.24.70]
13 80 ms 90 ms 90 ms 66.40.224.56

Using tracert

Don't run it while another process also trying to use tcp/ip from your machine. The results will be conflicted.

Look for something along these lines:

11 90 ms 90 ms 90 ms host189.hostcentric.com [209.25.214.189]
12 90 ms
*
*
VLAN5.FMT6509-1.hostcentric.com [66.40.24.70]
13 350 ms 380 ms 360 ms 66.40.224.56


This means that at hop 12, the node did respond more than once. Disregard the higher numbers following the problem node, since they are affected by the earlier issue. If you see three * on a line,

11 90 ms 90 ms 90 ms host189.hostcentric.com [209.25.214.189]
12
*
*
*
VLAN5.FMT6509-1.hostcentric.com [66.40.24.70]
13 350 ms 380 ms 360 ms 66.40.224.56

it signifies one of two issues: Either there is a serious network problem at this node, or the node is not configured to respond correctly to the 0 TTL sent to determine the node's characteristics.

Speed it up!

Want a quick look at the route information? Use the -d switch and tracert will not lookup the DNS for the node (you can do this with nslookup if you need information, or rerun tracert without the -d switch to find the offending node/server/router)

 


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