forked from extern/shorewall_code
Note that mss= in zones file should be accompanied by FASTACCEPT=No
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@7165 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
This commit is contained in:
parent
e8657289fc
commit
9afce0d59b
@ -55,7 +55,7 @@
|
||||
<tgroup align="left" cols="3">
|
||||
<tbody>
|
||||
<row>
|
||||
<entry><ulink url="Accounting.html">Accounting</ulink></entry>
|
||||
<entry></entry>
|
||||
|
||||
<entry><ulink url="PortKnocking.html#Limit">Limiting per-IPaddress
|
||||
Connection Rate</ulink></entry>
|
||||
@ -65,7 +65,7 @@
|
||||
</row>
|
||||
|
||||
<row>
|
||||
<entry><ulink url="Actions.html">Actions</ulink></entry>
|
||||
<entry><ulink url="Accounting.html">Accounting</ulink></entry>
|
||||
|
||||
<entry><ulink url="shorewall_logging.html">Logging</ulink></entry>
|
||||
|
||||
@ -74,8 +74,7 @@
|
||||
</row>
|
||||
|
||||
<row>
|
||||
<entry><ulink url="Shorewall_and_Aliased_Interfaces.html">Aliased
|
||||
(virtual) Interfaces (e.g., eth0:0)</ulink></entry>
|
||||
<entry><ulink url="Actions.html">Actions</ulink></entry>
|
||||
|
||||
<entry><ulink url="Macros.html">Macros</ulink></entry>
|
||||
|
||||
@ -84,8 +83,8 @@
|
||||
</row>
|
||||
|
||||
<row>
|
||||
<entry><ulink url="Anatomy.html">Anatomy of Shorewall</ulink>
|
||||
(<ulink url="Anatomy_ru.html">Russian</ulink>)</entry>
|
||||
<entry><ulink url="Shorewall_and_Aliased_Interfaces.html">Aliased
|
||||
(virtual) Interfaces (e.g., eth0:0)</ulink></entry>
|
||||
|
||||
<entry><ulink url="MAC_Validation.html">MAC
|
||||
Verification</ulink></entry>
|
||||
@ -95,8 +94,8 @@
|
||||
</row>
|
||||
|
||||
<row>
|
||||
<entry><ulink url="traffic_shaping.htm">Bandwidth Control</ulink>
|
||||
(<ulink url="traffic_shaping_ru.html">Russian</ulink>)</entry>
|
||||
<entry><ulink url="Anatomy.html">Anatomy of Shorewall</ulink>
|
||||
(<ulink url="Anatomy_ru.html">Russian</ulink>)</entry>
|
||||
|
||||
<entry><ulink url="Manpages.html">Man Pages</ulink></entry>
|
||||
|
||||
@ -104,6 +103,16 @@
|
||||
Guide</ulink></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
<entry><ulink url="traffic_shaping.htm">Bandwidth Control</ulink>
|
||||
(<ulink url="traffic_shaping_ru.html">Russian</ulink>)</entry>
|
||||
|
||||
<entry><ulink
|
||||
url="two-interface.htm#SNAT">Masquerading</ulink></entry>
|
||||
|
||||
<entry><ulink url="samba.htm">SMB</ulink></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
<entry><ulink url="blacklisting_support.htm">Blacklisting</ulink>
|
||||
(<ulink
|
||||
@ -113,7 +122,9 @@
|
||||
from a Single Firewall</ulink> (<ulink
|
||||
url="MultiISP_ru.html">Russian</ulink>)</entry>
|
||||
|
||||
<entry><ulink url="samba.htm">SMB</ulink></entry>
|
||||
<entry><ulink url="two-interface.htm#SNAT">SNAT</ulink>
|
||||
(<firstterm>Source Network Address
|
||||
Translation</firstterm>)</entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
@ -182,8 +193,9 @@
|
||||
</row>
|
||||
|
||||
<row>
|
||||
<entry><ulink url="two-interface.htm#DNAT">DNAT</ulink> (Port
|
||||
Forwarding)</entry>
|
||||
<entry><ulink url="two-interface.htm#DNAT">DNAT</ulink>
|
||||
(<firstterm>Destination Network Address
|
||||
Translation</firstterm>)</entry>
|
||||
|
||||
<entry><ulink url="starting_and_stopping_shorewall.htm">Operating
|
||||
Shorewall</ulink></entry>
|
||||
@ -197,6 +209,9 @@
|
||||
|
||||
<entry><ulink url="PacketMarking.html">Packet
|
||||
Marking</ulink></entry>
|
||||
|
||||
<entry><ulink url="upgrade_issues.htm">Upgrade
|
||||
Issues</ulink></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
@ -206,8 +221,7 @@
|
||||
<entry><ulink url="PacketHandling.html">Packet Processing in a
|
||||
Shorewall-based Firewall</ulink></entry>
|
||||
|
||||
<entry><ulink url="upgrade_issues.htm">Upgrade
|
||||
Issues</ulink></entry>
|
||||
<entry><ulink url="VPNBasics.html">VPN</ulink></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
@ -216,7 +230,8 @@
|
||||
|
||||
<entry><ulink url="ping.html">'Ping' Management</ulink></entry>
|
||||
|
||||
<entry><ulink url="VPNBasics.html">VPN</ulink></entry>
|
||||
<entry><ulink url="whitelisting_under_shorewall.htm">White List
|
||||
Creation</ulink></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
@ -225,8 +240,8 @@
|
||||
<entry><ulink url="two-interface.htm#DNAT">Port
|
||||
Forwarding</ulink></entry>
|
||||
|
||||
<entry><ulink url="whitelisting_under_shorewall.htm">White List
|
||||
Creation</ulink></entry>
|
||||
<entry><ulink url="XenMyWay.html">Xen - Shorewall in a Bridged Xen
|
||||
DomU</ulink></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
@ -235,8 +250,8 @@
|
||||
|
||||
<entry><ulink url="ports.htm">Port Information</ulink></entry>
|
||||
|
||||
<entry><ulink url="XenMyWay.html">Xen - Shorewall in a Bridged Xen
|
||||
DomU</ulink></entry>
|
||||
<entry><ulink url="XenMyWay-Routed.html">Xen - Shorewall in Routed
|
||||
Xen Dom0</ulink></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
@ -246,8 +261,7 @@
|
||||
<entry><ulink url="PortKnocking.html">Port Knocking and Other Uses
|
||||
of the 'Recent Match'</ulink></entry>
|
||||
|
||||
<entry><ulink url="XenMyWay-Routed.html">Xen - Shorewall in Routed
|
||||
Xen Dom0</ulink></entry>
|
||||
<entry></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
|
@ -460,6 +460,10 @@ sainfo address 192.168.1.0/24 any address 134.28.54.2/32 any
|
||||
# OPTIONS OPTIONS
|
||||
sec ipsec mode=tunnel <emphasis role="bold">mss=1400</emphasis></programlisting>
|
||||
|
||||
<para>You should also set FASTACCEPT=No in shorewall.conf to ensure
|
||||
that both the SYN and SYN,ACK packets have their MSS field
|
||||
adjusted.</para>
|
||||
|
||||
<para>Note that CLAMPMSS=Yes in <filename>shorewall.conf</filename>
|
||||
isn't effective with the 2.6 native IPSEC implementation because there
|
||||
is no separate ipsec device with a lower mtu as there was under the
|
||||
|
@ -16,7 +16,7 @@
|
||||
<pubdate><?dbtimestamp format="Y/m/d"?></pubdate>
|
||||
|
||||
<copyright>
|
||||
<year>2003-2006</year>
|
||||
<year>2003-2007</year>
|
||||
|
||||
<holder>Thomas M. Eastep</holder>
|
||||
</copyright>
|
||||
@ -108,6 +108,11 @@
|
||||
<para><ulink
|
||||
url="http://www.fs-security.com/">http://www.fs-security.com/</ulink></para>
|
||||
</listitem>
|
||||
|
||||
<listitem>
|
||||
<para><ulink
|
||||
url="http://www.fs-security.com/">http://www.fs-security.com/</ulink></para>
|
||||
</listitem>
|
||||
</itemizedlist>
|
||||
|
||||
<para>If you are looking for a Linux firewall solution that can handle
|
||||
|
@ -578,20 +578,22 @@ root@lists:~# </programlisting>
|
||||
<title>IP Masquerading (SNAT)</title>
|
||||
|
||||
<para>The addresses reserved by RFC 1918 are sometimes referred to as
|
||||
non-routable because the Internet backbone routers don't forward packets
|
||||
which have an RFC-1918 destination address. When one of your local systems
|
||||
(let's assume computer 1) sends a connection request to an internet host,
|
||||
the firewall must perform <emphasis>Network Address Translation</emphasis>
|
||||
(<acronym>NAT</acronym>). The firewall rewrites the source address in the
|
||||
packet to be the address of the firewall's external interface; in other
|
||||
words, the firewall makes it look as if the firewall itself is initiating
|
||||
the connection. This is necessary so that the destination host will be
|
||||
able to route return packets back to the firewall (remember that packets
|
||||
whose destination address is reserved by RFC 1918 can't be routed across
|
||||
the internet so the remote host can't address its response to computer 1).
|
||||
When the firewall receives a return packet, it rewrites the destination
|
||||
address back to <systemitem class="ipaddress">10.10.10.1</systemitem> and
|
||||
forwards the packet on to computer 1.</para>
|
||||
<firstterm>non-routable</firstterm> because the Internet backbone routers
|
||||
don't forward packets which have an RFC-1918 destination address. When one
|
||||
of your local systems (let's assume computer 1 in the <link
|
||||
linkend="Diagram">above diagram</link>) sends a connection request to an
|
||||
internet host, the firewall must perform <emphasis>Network Address
|
||||
Translation</emphasis> (<acronym>NAT</acronym>). The firewall rewrites the
|
||||
source address in the packet to be the address of the firewall's external
|
||||
interface; in other words, the firewall makes it appear to the destination
|
||||
internet host as if the firewall itself is initiating the connection. This
|
||||
is necessary so that the destination host will be able to route return
|
||||
packets back to the firewall (remember that packets whose destination
|
||||
address is reserved by RFC 1918 can't be routed across the internet so the
|
||||
remote host can't address its response to computer 1). When the firewall
|
||||
receives a return packet, it rewrites the destination address back to
|
||||
<systemitem class="ipaddress">10.10.10.1</systemitem> and forwards the
|
||||
packet on to computer 1.</para>
|
||||
|
||||
<para>On Linux systems, the above process is often referred to as
|
||||
<emphasis>IP Masquerading</emphasis> but you will also see the term
|
||||
@ -611,8 +613,8 @@ root@lists:~# </programlisting>
|
||||
</listitem>
|
||||
</itemizedlist> In Shorewall, both <emphasis>Masquerading</emphasis> and
|
||||
<emphasis><acronym>SNAT</acronym></emphasis> are configured with entries
|
||||
in the <filename
|
||||
class="directory">/etc/shorewall/</filename><filename>masq</filename>
|
||||
in the <ulink url="manpages/shorewall-masq.html"><filename
|
||||
class="directory">/etc/shorewall/</filename><filename>masq</filename></ulink>
|
||||
file. You will normally use Masquerading if your external
|
||||
<acronym>IP</acronym> is dynamic and <acronym>SNAT</acronym> if the
|
||||
<acronym>IP</acronym> is static.</para>
|
||||
@ -621,7 +623,8 @@ root@lists:~# </programlisting>
|
||||
|
||||
<para>If your external firewall interface is <filename
|
||||
class="devicefile">eth0</filename>, you do not need to modify the file
|
||||
provided with the sample. Otherwise, edit <filename
|
||||
provided with <link linkend="Concepts">the sample</link>. Otherwise, edit
|
||||
<filename
|
||||
class="directory">/etc/shorewall/</filename><filename>masq</filename> and
|
||||
change the first column to the name of your external interface and the
|
||||
second column to the name of your internal interface.</para>
|
||||
@ -632,8 +635,9 @@ root@lists:~# </programlisting>
|
||||
in the third column in the <filename
|
||||
class="directory">/etc/shorewall/</filename><filename>masq</filename>
|
||||
entry if you like although your firewall will work fine if you leave that
|
||||
column empty. Entering your static <acronym>IP</acronym> in column 3 makes
|
||||
processing outgoing packets a little more efficient.</para>
|
||||
column empty (Masquerade). Entering your static <acronym>IP</acronym> in
|
||||
column 3 (SNAT) makes the processing of outgoing packets a little more
|
||||
efficient.</para>
|
||||
|
||||
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
|
||||
|
||||
|
@ -167,7 +167,11 @@ c:a,b ipv4</programlisting>
|
||||
role="bold">mss=</emphasis><emphasis>number</emphasis></term>
|
||||
|
||||
<listitem>
|
||||
<para>sets the MSS field in TCP packets</para>
|
||||
<para>sets the MSS field in TCP packets. If you supply this
|
||||
option, you should also set FASTACCEPT=No in <ulink
|
||||
url="shorewall.conf.html">shorewall.conf</ulink>(8) to insure
|
||||
that both the SYN and SYN,ACK packets have their MSS field
|
||||
adjusted.</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user