in windows go to a dos prompt and type tracert hostname IE:
tracert
www.somehost.com
The results will look like this:
Tracing route to yahoo.com [66.94.234.13]
over a maximum of 30 hops:
1 19 ms 15 ms 17 ms 68.152.193.53
2 18 ms 16 ms 17 ms 68.152.193.57
3 28 ms 28 ms 29 ms adsl-152-88-50.ard.bellsouth.net [205.152.88.50]
4 38 ms 38 ms 42 ms axr00asm-7-2-0-0.bellsouth.net [65.83.237.56]
5 38 ms 38 ms 40 ms axr01asm-0-2-0.bellsouth.net [65.83.236.9]
6 42 ms 39 ms 40 ms AXR00AEP-0-1-0.bellsouth.net [65.83.236.50]
7 50 ms 50 ms 50 ms 65.83.236.66
8 54 ms 54 ms 50 ms 65.83.237.254
9 111 ms 111 ms 113 ms ge-0-1-4.p149.pat2.pao.yahoo.com [216.115.96.32]
10 112 ms 121 ms 111 ms ge-1-0-9.msr2.scd.yahoo.com [216.115.101.46]
11 117 ms 110 ms 109 ms UNKNOWN-66-218-82-238.yahoo.com [66.218.82.238]
12 118 ms 110 ms 117 ms w2.rc.vip.scd.yahoo.com [66.94.234.13]
Trace complete.
You can then look at times and look for cogent.
To see what your host is using for outbound traffic you can do this from a shell account on your host and type traceroute somehost.com.