This is stuff that used to be in the Networking lectures, but isn't anymore because basically there's no going back with how security has change on the Internet.  However, I decided to keep it around as historical documentation.

  1. However, for security reasons, many of these services are by default turned off these days.
    1. The below (in purple) is for hackers only!!
    2. If you do this stuff & your box gets hacked, don't blame me!  You need to undo it again before you plug back into the internet!
    3. If you have installed linux on your own computer, you might want to turn these on & play with them. 
      1. However, note that you should probably turn them back off again before plugging your computer back into the internet if you do!
      2. Note that this has to be your own linux box, because you need superuser (root) access to do this.
        1.  If you don't know what this means don't worry -- there are other examples below that don't require this, that you can run, like the linelength server.
        2. But do still have a look at what the servers do, so you can understand the code of what a client does that talks to it.
        3. I demonstrate how to do this below in the main (non purple) lecture notes.
    4. Mac OS X used to be almost linux.  the below worked on 10.3, but I left my 10.3 laptop in Maastsricht so couldn't demo this for you, sorry.
      1. To get this working there, I had to edit /etc/xinetd.d/{daytime,echo} to set disable from yes to no.
      2. Then I had to restart xinetd:  Vigor11:/etc root# service xinetd restart
        No such service xinetd
      3. Too linux / too easy!
      4. ps -auxw | egrep xine
        root       285   0.0  0.0    27484     44  ??  Ss    5Feb07   0:00.01 xinetd -inetd_compat -pidfile /var/run/xinetd.pid
        Vigor11:~ root# kill -HUP 285
        Vigor11:~ root# ps -auxw | egrep xine
        root       285   0.0  0.0    27484    300  ??  Ss    5Feb07   0:00.04 xinetd -inetd_compat -pidfile /var/run/xinetd.pid
        root      7034   0.0  0.0    18644    208 std  R+    8:56PM   0:00.00 egrep xine
        Vigor11:~ root# kill -KILL 285
        Vigor11:~ root# ps -auxw | egrep xine
        root      7036   0.0  0.0    18644    208 std  R+    8:56PM   0:00.00 egrep xine
        Vigor11:~ root#
        Vigor11:~ root# /System/Library/StartupItems/IPServices/IPServices start
        Starting internet services
        Vigor11:~ root# ps -auxw | egrep xine
        root      7040   0.0  0.1    27484    704  ??  Ss    8:57PM   0:00.02 xinetd -inetd_compat -pidfile /var/run/xinetd.pid
        root      7042   0.0  0.0    18644    208 std  R+    8:57PM   0:00.00 egrep xine
        Vigor11:~ root#
      5. You should never really have to kill -KILL anything... it means "don't clean up your children, just DIE".
        1. As with last week's discussion of death, the unix utility "kill" just sends a signal, and the first argument is which signal it sends.  The second is the process ID.
  2. Thea:~ joanna$ traceroute google.cn
    traceroute to google.cn (74.125.95.160), 64 hops max, 40 byte packets
     1  api (192.168.1.254)  207.080 ms  1.288 ms  1.407 ms
     2  217.32.141.0 (217.32.141.0)  21.465 ms  21.697 ms  22.224 ms
     3  217.32.140.222 (217.32.140.222)  21.994 ms  21.916 ms  22.787 ms
     4  213.120.161.34 (213.120.161.34)  27.092 ms  27.571 ms  27.340 ms
     5  217.41.222.10 (217.41.222.10)  29.634 ms  28.298 ms  28.629 ms
     6  217.41.222.178 (217.41.222.178)  27.234 ms  29.000 ms  27.248 ms
     7  217.41.222.121 (217.41.222.121)  28.240 ms  27.720 ms  27.585 ms
     8  core2-gig4-0-0.birmingham.ukcore.bt.net (217.32.170.73)  29.601 ms  29.640 ms  30.760 ms
     9  core2-pos0-6-4-0.ilford.ukcore.bt.net (62.6.204.62)  33.862 ms  32.878 ms  32.726 ms
    10  core4te-0-7-1-0.telehouse.ukcore.bt.net (62.172.102.29)  34.553 ms  34.498 ms  33.860 ms
    11  195.99.125.82 (195.99.125.82)  32.650 ms  32.983 ms  31.632 ms
    12  209.85.255.175 (209.85.255.175)  34.109 ms  33.490 ms 209.85.252.76 (209.85.252.76)  32.848 ms
    13  216.239.43.192 (216.239.43.192)  107.529 ms 209.85.250.54 (209.85.250.54)  133.474 ms  101.692 ms
    14  209.85.251.233 (209.85.251.233)  123.811 ms  123.294 ms  123.764 ms
    15  72.14.232.141 (72.14.232.141)  139.370 ms  135.284 ms  133.270 ms
    16  209.85.241.27 (209.85.241.27)  163.011 ms  143.349 ms 209.85.241.35 (209.85.241.35)  142.509 ms
    17  209.85.240.49 (209.85.240.49)  142.248 ms 72.14.239.189 (72.14.239.189)  139.446 ms 209.85.240.49 (209.85.240.49)  141.200 ms
    18  iw-in-f160.1e100.net (74.125.95.160)  140.527 ms  145.639 ms  136.314 ms
    Thea:~ joanna$ 
  3. That's actually through BT (from my home) -- in the main lecture I showed it from the CS department: