shorewall-nat
5
nat
Shorewall one-to-one NAT file
/etc/shorewall/nat
Description
This file is used to define one-to-one Network Address Translation
(NAT).
If all you want to do is simple port forwarding, do NOT use this
file. See http://www.shorewall.net/FAQ.htm#faq1.
Also, in many cases, Proxy ARP (shorewall-proxyarp(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.
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(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(5).
Shorewall allows loose matches to wildcard entries in shorewall-interfaces(5). For
example, ppp0 in this file
will match a shorewall-interfaces(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://www.shorewall.net/NAT.htm
http://www.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-mangle(5), shorewall-tos(5), shorewall-tunnels(5),
shorewall-zones(5)