traceroute internet.address
Traceroute is an interesting utility to find out where your packets have to go to get to a specific place. It can be useful to determine if there is a problem somewhere between the machine you're on and the one you want to get to.

Example:
  1. See what it takes to get from thunder to gatekeeper.dec.com:
    mama:~> traceroute gatekeeper.dec.com
    
    traceroute to gatekeeper.dec.com (16.1.0.2), 30 hops max, 40 byte packets
     1  139.102.70.1 (139.102.70.1)  2.491 ms  2.38 ms  2.422 ms
     2  139.102.1.254 (139.102.1.254)  2.429 ms  2.434 ms  2.601 ms
     3  157.91.212.12 (157.91.212.12)  7.699 ms  7.676 ms  8.127 ms
     4  bloomingtons1.ind.net (157.91.2.11)  14.946 ms  14.4 ms  18.816 ms
     5  iub-gw-ihets.ucs.indiana.edu (140.182.5.1)  13.88 ms  13.85 ms  14.031 ms
     6  cicnet-gw.ucs.indiana.edu (129.79.5.131)  17.211 ms  14.892 ms  18.665 ms
     7  dgc-iu.cic.net (131.103.26.193)  44.439 ms  35.378 ms  49.437 ms
     8  dgf-fddi0.cic.net (131.103.1.19)  35.912 ms  38.456 ms  32.456 ms
     9  192.217.0.1 (192.217.0.1)  46.723 ms  45.123 ms  34.037 ms
    10  border1-hssi1/0.Chicago.mci.net (204.70.24.5) 41.155 ms 39.134 ms 32.085 ms
    11  * core-fddi-0.Chicago.mci.net (204.70.2.81)  33.581 ms  33.237 ms
    12  core-hssi-3.Seattle.mci.net (204.70.1.30)  84.641 ms  84.57 ms  90.878 ms
    13  core-hssi-2.SanFrancisco.mci.net (204.70.1.50) 103.118ms 99.17ms 103.06 ms
    14  border1-fddi0/0.SanFrancisco.mci.net (204.70.2.162) 102.245ms 106.523ms 
    15  cpe1-hssi-1.SanFrancisco.mci.net (204.70.32.6) 106.232ms 103.649ms 126.10
    16  SSP.BARRNET.NET (192.31.48.202)  104.212 ms  111.835 ms  102.85 ms
    17  DEC-SU.BARRNET.NET (192.31.50.2)  114.794 ms  108.647 ms  108.02 ms
    18  gatekeeper.dec.com (16.1.0.2)  118.6 ms  135.713 ms  114.879 ms
    

    Wow... It's almost amazing the network is as fast as it is.