tracetcp vs tracert

Many sites block ICMP pings, which makes the use of the traditional route tracing tools difficult, as can be seen by the following trace, which uses the standard Windows tracert utility:

$ tracert www.ebay.co.uk

Tracing route to www.ebay.co.uk [66.135.192.41]
over a maximum of 30 hops:

  1     1 ms     1 ms     1 ms  wintermute [192.168.0.1]
  2    10 ms     9 ms     9 ms  10.78.128.1
  3    10 ms     9 ms    10 ms  gsr01-so.blueyonder.co.uk [62.30.193.33]
  4     9 ms     9 ms    10 ms  172.18.14.45
  5    13 ms    13 ms    13 ms  172.18.14.62
  6    13 ms    13 ms    14 ms  tele2-witt-pos.telewest.net [194.117.136.18]
  7    14 ms    13 ms    14 ms  zcr1-so-5-0-0.Londonlnt.cw.net [166.63.222.37]
  8   168 ms   164 ms   162 ms  dcr2-loopback.SantaClara.cw.net [208.172.146.100]
  9   165 ms   164 ms   163 ms  bhr1-pos-0-0.SantaClarasc8.cw.net [208.172.156.198]
 10   164 ms   163 ms   165 ms  csr1-ve243.SantaClarasc8.cw.net [66.35.194.50]
 11     *        *        *     Request timed out.
 12     *        *        *     Request timed out.
 13  .... continues until maximum number of hops reached.

Looking at the above trace it is impossible to determine if an intermediate router (at hop 11) has failed or the probes are being blocked.

By using tracetcp we are able to probe all the way to the host machine. Note, however some routers do not report time-to-live exceeded messages as can be by hop #14. From this trace we can see that our packets are reaching the host machine and that it is accepting connections on the specified port (in this case 80).

$ tracetcp www.ebay.co.uk

Tracing route to 66.135.192.41 [www.ebay.co.uk] on port 80
Over a maximum of 30 hops.
1       1 ms    1 ms    2 ms    192.168.0.1     [wintermute]
2       10 ms   9 ms    11 ms   10.78.128.1
3       10 ms   11 ms   8 ms    62.30.193.33    [gsr01-so.blueyonder.co.uk]
4       10 ms   9 ms    10 ms   172.18.14.45
5       14 ms   13 ms   14 ms   172.18.14.62
6       12 ms   13 ms   14 ms   194.117.136.18  [tele2-witt-pos.telewest.net]
7       12 ms   12 ms   14 ms   166.63.222.37   [zcr1-so-5-0-0.Londonlnt.cw.net]
8       182 ms  164 ms  164 ms  208.172.146.100 [dcr2-loopback.SantaClara.cw.net]
9       163 ms  163 ms  164 ms  208.172.156.198 [bhr1-pos-0-0.SantaClarasc8.cw.net]
10      165 ms  165 ms  167 ms  66.35.194.50    [csr1-ve243.SantaClarasc8.cw.net]
11      165 ms  165 ms  164 ms  66.35.212.190
12      168 ms  169 ms  169 ms  66.135.207.253
13      166 ms  169 ms  171 ms  66.135.207.174
14      *       *       *       Request timed out.
15      Destination Reached in 170 ms. Connection established to 66.135.192.41
Trace Complete.
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