** lab7
*** task
    | No. | Client part    | Server | Special       | Count  | Log           |
    |   5 | FTP to net     | SMTP   | IP in/out     | In TCP | In from net   |
    |     | 10.18.49.0/24, |        | 10.18.48.0/24 |        | 10.18.51.0/24 |
    |     | POP3           |        |               |        |               |
*** solution
    #+begin_src sh
    ipfw add 1 allow ip from any to any via lo0
    ipfw add 2 count tcp from any to me
    ipfw add 3 allow log ip from 10.18.51.0/24 to me
    # FTP
    ipfw add 4 allow ip from me to 10.18.49.0/24 dst-port 20-21
    # POP3
    ipfw add 5 allow ip from me to any dst-port 110
    # SMTP
    ipfw add 6 allow ip from any to me dst-port 25
    # special
    ipfw add 7 allow ip from 10.18.48.0/24 to me
    ipfw add 8 allow ip from me to 10.18.48.0/24
    #+end_src