Statistics from pfctl

You may want to check that PF is actually running, and perhaps at the same time look at some statistics. The pfctl program offers a number of different types of information if you use pfctl -s, adding the type of information you want to display. The following example is taken from my home gateway while I was preparing an earlier version of this lecture:

$ sudo pfctl -s info
Status: Enabled for 17 days 00:24:58          Debug: Urgent

Interface Stats for ep0               IPv4             IPv6
  Bytes In                      9257508558                0
  Bytes Out                      551145119              352
  Packets In
    Passed                         7004355                0
    Blocked                          18975                0
  Packets Out
    Passed                         5222502                3
    Blocked                             65                2

State Table                          Total             Rate
  current entries                       15               
  searches                        19620603           13.3/s
  inserts                           173104            0.1/s
  removals                          173089            0.1/s
Counters
  match                             196723            0.1/s
  bad-offset                             0            0.0/s
  fragment                              22            0.0/s
  short                                  0            0.0/s
  normalize                              0            0.0/s
  memory                                 0            0.0/s
  bad-timestamp                          0            0.0/s
  congestion                             0            0.0/s
  ip-option                             28            0.0/s
  proto-cksum                          325            0.0/s
  state-mismatch                       983            0.0/s
  state-insert                           0            0.0/s
  state-limit                            0            0.0/s
  src-limit                             26            0.0/s
  synproxy                               0            0.0/s

The first line here indicates that PF is enabled and has been running for for a little more than two weeks, which is equal to the time since I upgraded to what was then the latest snapshot. pfctl -s all provides highly detailed information. Try it and have a look, and while there, look into some of the other pfctl options. man 8 pfctl gives you full information.

At this point you have a single machine which should be able to communicate reasonably well with other internet connected machines. And while the rule set is very basic, it serves as an excellent starting point for staying in control of your network.

This is a very basic rule set and a few things are still missing. For example, you probably want to let at least some ICMP and UDP traffic through, if nothing else for your own troubleshooting needs.

And even though more modern and more secure options are available, you will probably be required to handle the ftp service.

We will return to these items shortly.