FreeBSD nat with pf

This is a basic script with some commands to enable nat with pf.


pfctl -e        #to enable pf
pfctl -nf /etc/pf.conf  #to parse rules from /etc/pf.conf file
kldload pf  #to load pf module
pfctl -f /etc/pf.conf   #to load rules from /etc/pf.conf file


To flush nat:
pfctl -F nat
A.B.C.D is the public IP put on em0 interface.

==================
#cat /etc/pf.conf  #this is pf configuration file
nat on em0 from 172.16.16.0/24 to any -> A.B.C.D
###binat on em0 from 172.16.16.2/32 to any -> A.B.C.D
rdr on { em0 re1 }  proto udp from any to A.B.C.D port 10011 -> 172.16.16.2 port 10011
rdr on { em0 re1 }  proto tcp from any to A.B.C.D port 2222 -> 172.16.16.2 port 22

=================
# pfctl -sn           #to view active rules
nat on em0 inet from 172.16.16.0/24 to any -> 89.137.197.15
rdr on em0 inet proto udp from any to A.B.C.D port = 10011 -> 172.16.16.2 port 10011
rdr on re1 inet proto udp from any to A.B.C.D port = 10011 -> 172.16.16.2 port 10011

=================
# pfctl -v -s nat      #to view if nat is working
No ALTQ support in kernel
ALTQ related functions disabled
nat on em0 inet from 172.16.16.0/24 to any -> A.B.C.D
  [ Evaluations: 171531    Packets: 158       Bytes: 11732       States: 1     ]
  [ Inserted: uid 0 pid 15527 State Creations: 1     ]
rdr on em0 inet proto udp from any to A.B.C.D port = 10011 -> 172.16.16.2 port 10011
  [ Evaluations: 266473    Packets: 46286     Bytes: 64392976    States: 2     ]
  [ Inserted: uid 0 pid 15527 State Creations: 2     ]

==================
#pfctl -F nat       # to flush rules from nat table