pf.conf specified by using these operators

Ports and ranges of ports are specified by using these operators:

= (equal)
!= (unequal)
< (less than)
<= (less than or equal)
> (greater than)
>= (greater than or equal)
: (range including boundaries)
>< (range excluding boundaries)
<> (except range)

><, <> and : are binary operators (they take two arguments). For instance:

port 2000:2004
means `all ports >= 2000 and <= 2004′, hence ports
2000, 2001, 2002, 2003 and 2004.

port 2000 __ 2004
means `all ports > 2000 and < 2004′, hence ports 2001,
2002 and 2003.

port 2000 __ 2004
means `all ports < 2000 or > 2004′, hence ports 1-1999
and 2005-65535.