Section H-5. traceroute and tracert


H-5. traceroute and tracert

The traceroute command traces paths through routers. Depending on the system you're using, the name of this command may vary. On the Linux system we used, it's called tcptraceroute:

 $ /usr/bin/tcptraceroute www.yahoo.com Selected device eth0, address 192.168.0.48, port 33633 for outgoing packets Tracing the path to www.yahoo.com (68.142.226.56) on TCP port 80 (www), 30 hops max 1  192.168.0.1  11.811 ms  0.372 ms  0.352 ms 2  69.15.40.49  1.623 ms  1.331 ms  1.331 ms 3  172.16.141.177  3.371 ms  3.314 ms  3.216 ms 4  192.168.14.21  3.629 ms  3.599 ms  3.703 ms 5  192.168.34.10  4.491 ms  4.395 ms  4.447 ms 6  ge-9-0-133.hsa1.Atlanta1.Level3.net (209.246.169.33)  4.745 ms 5.025 ms  4.472 ms 7  ge-6-1-0.bbr1.Atlanta1.Level3.net (64.159.3.5)  9.875 ms  5.234 ms  4.710 ms 8  ae-0-0.bbr1.Washington1.Level3.net (64.159.0.229)  17.875 ms 18.737 ms  17.529 ms 9  ge-3-0-0-55.gar1.Washington1.Level3.net (4.68.121.130)  17.824 ms 17.813 ms  18.275 ms 10  63.210.29.230  18.314 ms  18.504 ms  18.742 ms 11  vl4.bas1.re2.yahoo.com (206.190.33.10)  18.549 ms  18.577 ms  18.305 ms 12  p25.www.re2.yahoo.com (68.142.226.56) [open]  18.596 ms  18.499 ms 18.783 ms $ 

Windows' tracert is identical to traceroute, except it uses ICMP packets rather than UDP packets to discover the paths between routers:

 C:\>tracert www.yahoo.com   Tracing route to www.yahoo.akadns.net [216.109.117.108] over a maximum of 30 hops:     1    10 ms     7 ms     9 ms  10.239.230.1   2    10 ms     8 ms     9 ms  68.86.109.157   3    10 ms    10 ms     8 ms  68.86.106.178   4     9 ms     9 ms     9 ms  68.86.106.182   5    10 ms     9 ms    10 ms  68.86.106.186   6    15 ms    17 ms     9 ms  68.86.106.190   7    10 ms    10 ms     9 ms  68.86.106.158   8    10 ms    10 ms     8 ms  68.86.107.13   9    10 ms     9 ms    10 ms  12.124.64.21  10    11 ms    11 ms    11 ms  tbr1-p013701.attga.ip.att.net [12.123.21.98]  11    24 ms    24 ms    24 ms  tbr2-cl1.wswdc.ip.att.net [12.122.10.69]  12    24 ms    24 ms    23 ms  gar1-p390.ascva.ip.att.net [12.123.8.53]  13     *        *        *     Request timed out.  14    32 ms    25 ms    24 ms  ae1.p400.msr1.dcn.yahoo.com [216.115.96.181]  15    25 ms    23 ms    25 ms  ge7-1.bas1-m.dcn.yahoo.com [216.109.120.205]  16    25 ms    25 ms    25 ms  p23.www.dcn.yahoo.com [216.109.117.108]   Trace complete. 

Here are some points to remember when using traceroute:

  • In the output from both traceroute and tracert, the path was 16 hops.

  • Times are printed for each of the three probes sent.

  • An asterisk is printed in place of the time when a packet is lost.

  • Additional messages can be appended to the end of each line: !H, !N, and !P indicate, respectively, that the host, network, or protocol is unreachable. !F indicates that fragmentation is needed. !S indicates a source route failure.

  • The path taken from destination to source may not be the same path taken from source to destination, due to different path routes.




Essential SNMP
Essential SNMP, Second Edition
ISBN: 0596008406
EAN: 2147483647
Year: 2003
Pages: 165

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