Refer from http://www.freebsd.org/doc/en/books/handbook/firewalls-ipf.html
When supplied with either
-i for inbound or
-o for outbound, it will retrieve and display the appropriate list of filter rules currently installed and in use by the kernel.
ipfstat -in displays the inbound internal rules table with rule number.
ipfstat -on displays the outbound internal rules table with the rule number.
The output will look something like this:
@1 pass out on xl0 from any to any
@2 block out on dc0 from any to any
@3 pass out quick on dc0 proto tcp/udp from any to any keep state