   ,   :

1.   ethi (  LAN): -i ethl.

2.    ethO (  Internet): - ethO.

  ,    ,  , 
    ,   Internet. 
    /.  
     FORWARD.

       FORWARD  FILTER:

# iptables -A FORWARD -j LOG

     ,      -
  .        ;  -
,       Internet,    
.

,      FORWARD  FILTER, 
 ,  iptables,    -
  TCP.   Internet,     -
  ,   ,    , 
    ,     .

       POSTROUTING 
NAT.   NAT   ,   .
      SNAT  MASQUERADE -
   ESTABLISHED  RELATED   ,   
 .  ,      ,  
,       ,

# iptables -t NAT -A POSTROUTING - ethO -j MASQUERADE
   ,   :

1.    (       NAT).

2.    ethO (  Internet): - ethO.

   ,   ,  ,  
   ,     -
    ,    ethO (  
10.255.255.255).

    :

 iptables -A FORWARD -i ethO - ethl -m state state ESTABLISHED,RELATED -j ACCEPT

# iptables -A FORWARD -i ethl -o ethO -j ACCEPT
t iptables -A FORWARD -j LOG

# iptables -t NAT -A POSTROUTING -o ethO -j MASQUERADE

      /etc/rc. local   , 
    ,      
.       /etc/sysconfig/iptables,  
iptables    .      iptables,  -
   iptables    . 
    "      "   
.

774                            V.     