NAME

       nat - Shorewall one-to-one NAT file

SYNOPSIS

       /etc/shorewall/nat

DESCRIPTION

       This file is used to define one-to-one Network Address Translation (NAT).

           Warning
           If all you want to do is simple port forwarding, do NOT use this file. See
           http://www.shorewall.net/FAQ.htm#faq1[1]. Also, in many cases, Proxy ARP
           (shorewall-proxyarp[2](5)) is a better solution that one-to-one NAT.

       The columns in the file are as follows (where the column name is followed by a different
       name in parentheses, the different name is used in the alternate specification syntax).

       EXTERNAL - {address|[?]COMMENT}
           External IP Address - this should NOT be the primary IP address of the interface named
           in the next column and must not be a DNS Name.

           If you put COMMENT in this column, the rest of the line will be attached as a comment
           to the Netfilter rule(s) generated by the following entries in the file. The comment
           will appear delimited by "/* ... */" in the output of "shorewall show nat"

           To stop the comment from being attached to further rules, simply include COMMENT on a
           line by itself.

               Note
               Beginning with Shorewall 4.5.11, ?COMMENT is a synonym for COMMENT and is
               preferred.

       INTERFACE - interfacelist[:[digit]]
           Interfaces that have the EXTERNAL address. If ADD_IP_ALIASES=Yes in
           shorewall.conf[3](5), Shorewall will automatically add the EXTERNAL address to this
           interface. Also if ADD_IP_ALIASES=Yes, you may follow the interface name with ":" and
           a digit to indicate that you want Shorewall to add the alias with this name (e.g.,
           "eth0:0"). That allows you to see the alias with ifconfig.  That is the only thing
           that this name is good for -- you cannot use it anywhere else in your Shorewall
           configuration.

           Each interface must match an entry in shorewall-interfaces[4](5). Shorewall allows
           loose matches to wildcard entries in shorewall-interfaces[4](5). For example, ppp0 in
           this file will match a shorewall-interfaces[4](5) entry that defines ppp+.

           If you want to override ADD_IP_ALIASES=Yes for a particular entry, follow the
           interface name with ":" and no digit (e.g., "eth0:").

       INTERNAL - address
           Internal Address (must not be a DNS Name).

       ALL INTERFACES (allints) - [Yes|No]
           If Yes or yes, NAT will be effective from all hosts. If No or no (or left empty) then
           NAT will be effective only through the interface named in the INTERFACE column.

       LOCAL - [Yes|No]
           If Yes or yes, NAT will be effective from the firewall system

FILES

       /etc/shorewall/nat

SEE ALSO

       http://shorewall.net/NAT.htm

       http://shorewall.net/configuration_file_basics.htm#Pairs

       shorewall(8), shorewall-accounting(5), shorewall-actions(5), shorewall-blacklist(5),
       shorewall-hosts(5), shorewall_interfaces(5), shorewall-ipsets(5), shorewall-maclist(5),
       shorewall-masq(5), shorewall-netmap(5), shorewall-params(5), shorewall-policy(5),
       shorewall-providers(5), shorewall-proxyarp(5), shorewall-rtrules(5),
       shorewall-routestopped(5), shorewall-rules(5), shorewall.conf(5), shorewall-secmarks(5),
       shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5), shorewall-tos(5),
       shorewall-tunnels(5), shorewall-zones(5)

NOTES

        1. http://www.shorewall.net/FAQ.htm#faq1
           http://www.shorewall.net../FAQ.htm#faq1

        2. shorewall-proxyarp
           http://www.shorewall.netshorewall-proxyarp.html

        3. shorewall.conf
           http://www.shorewall.netshorewall.conf.html

        4. shorewall-interfaces
           http://www.shorewall.netshorewall-interfaces.html

[FIXME: source]                             01/30/2014                           SHOREWALL-NAT(5)