mirror of
https://gitlab.com/shorewall/code.git
synced 2024-12-22 14:20:40 +01:00
b7b4f6d2e8
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@192 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
87 lines
3.8 KiB
HTML
87 lines
3.8 KiB
HTML
<html>
|
||
|
||
<head>
|
||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||
<title>Shorewall NAT</title>
|
||
<meta name="GENERATOR" content="Microsoft FrontPage 5.0">
|
||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||
<meta name="Microsoft Theme" content="boldstri 011, default">
|
||
</head>
|
||
|
||
<body>
|
||
|
||
<blockquote>
|
||
<h1 align="center">Static NAT</h1>
|
||
<p><font color="#FF0000"><b>IMPORTANT: If all you want to do is forward
|
||
ports to servers behind your firewall, you do NOT want to use static NAT.
|
||
Port forwarding can be accomplished with simple entries in the
|
||
<a href="Documentation.htm#Rules">rules file</a>.</b></font></p>
|
||
<p>Static NAT is a way to make systems behind a
|
||
firewall and configured with private IP addresses (those
|
||
reserved for private use in RFC1918) appear to have public IP
|
||
addresses.</p>
|
||
<p>The following figure represents a static NAT
|
||
environment.</p>
|
||
<p align="center"><strong>
|
||
<img src="images/staticnat.png" width="435" height="397"></strong></p>
|
||
<blockquote>
|
||
</blockquote>
|
||
<p align="left">Static NAT can be used to make the systems with the
|
||
10.1.1.* addresses appear to be on the upper (130.252.100.*) subnet. If we
|
||
assume that the interface to the upper subnet is eth0, then the following
|
||
/etc/shorewall/NAT file would make the lower left-hand system appear to have
|
||
IP address 130.252.100.18 and the right-hand one to have IP address
|
||
130.252.100.19.</p>
|
||
<table border="2" cellpadding="2" style="border-collapse: collapse">
|
||
<tr>
|
||
<td><b>EXTERNAL</b></td>
|
||
<td><b>INTERFACE</b></td>
|
||
<td><b>INTERNAL</b></td>
|
||
<td><b>ALL INTERFACES</b></td>
|
||
<td><b>LOCAL</b></td>
|
||
</tr>
|
||
<tr>
|
||
<td>130.252.100.18</td>
|
||
<td>eth0</td>
|
||
<td>10.1.1.2</td>
|
||
<td>yes</td>
|
||
<td>yes</td>
|
||
</tr>
|
||
<tr>
|
||
<td>130.252.100.19</td>
|
||
<td>eth0</td>
|
||
<td>10.1.1.3</td>
|
||
<td>yes</td>
|
||
<td>yes</td>
|
||
</tr>
|
||
</table>
|
||
<p>Be sure that the internal system(s) (10.1.1.2 and 10.1.1.3 in the above
|
||
example) is (are) not included in any specification in /etc/shorewall/masq
|
||
or /etc/shorewall/proxyarp.</p>
|
||
<p><a name="AllInterFaces"></a>Note 1: The "ALL INTERFACES" column
|
||
is used to specify whether access to the external IP from all firewall
|
||
interfaces should undergo NAT (Yes or yes) or if only access from the
|
||
interface in the INTERFACE column should undergo NAT. If you leave this
|
||
column empty, "Yes" is assumed. The ALL INTERFACES column was
|
||
added in version 1.1.6.</p>
|
||
<p>Note 2: Shorewall will automatically add the external address to the
|
||
specified interface unless you specify <a href="Documentation.htm#Aliases">ADD_IP_ALIASES</a>="no"
|
||
(or "No") in /etc/shorewall/shorewall.conf; If you do not set
|
||
ADD_IP_ALIASES or if you set it to "Yes" or "yes" then you must NOT configure your own alias(es).</p>
|
||
<p><a name="LocalPackets"></a>Note 3: The contents of the "LOCAL"
|
||
column determine whether packets originating on the firewall itself and
|
||
destined for the EXTERNAL address are redirected to the internal ADDRESS. If
|
||
this column contains "yes" or "Yes" (and the ALL
|
||
INTERFACES COLUMN also contains "Yes" or "yes") then
|
||
such packets are redirected; otherwise, such packets are not redirected. The
|
||
LOCAL column was added in version 1.1.8.</p>
|
||
</blockquote>
|
||
|
||
<blockquote>
|
||
</blockquote>
|
||
|
||
<p><font size="2">Last updated 3/27/2002 - </font><font size="2">
|
||
<a href="support.htm">Tom
|
||
Eastep</a></font> </p>
|
||
<font face="Trebuchet MS"><a href="copyright.htm"><font size="2">Copyright</font>
|
||
<EFBFBD> <font size="2">2001, 2002 Thomas M. Eastep.</font></a></font></body></html> |