Hi, there is a small bug on http://www.openbsd.org/faq/pf/filter.html page. Here http://www.openbsd.org/faq/pf/filter.html#syntax , in section src_addr, dst_addr it says :
In addition, the :0 modifier can be appended to either an interface name or to any of the above modifiers to indicate that PF should not include aliased IP addresses in the substitution. These modifiers can also be used when the interface is contained in parentheses. Example: fxp0:network:0 But there are not parentheses around fxp0
