<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> <article id="PPTP"> <articleinfo> <title>PPTP</title> <authorgroup> <author> <firstname>Tom</firstname> <surname>Eastep</surname> </author> </authorgroup> <pubdate>2003-12-23</pubdate> <copyright> <year>2001</year> <year>2002</year> <year>2003</year> <holder>Thomas M. Eastep</holder> </copyright> <legalnotice> <para>Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover, and with no Back-Cover Texts. A copy of the license is included in the section entitled "<ulink url="GnuCopyright.htm">GNU Free Documentation License</ulink>".</para> </legalnotice> <revhistory> <revision> <revnumber>1.1</revnumber> <date>2003-12-23</date> <authorinitials>TE</authorinitials> <revremark>Added note about PPTP module support in Bering 1.2</revremark> </revision> </revhistory> <abstract> <para>Shorewall easily supports PPTP in a number of configurations.</para> </abstract> </articleinfo> <section> <title>Overview</title> <note> <para>I am no longer attempting to maintain MPPE patches for current Linux kernel's and pppd. I recommend that you refer to the following URLs for information about installing MPPE into your kernel and pppd.</para> </note> <para>The <ulink url="http://pptpclient.sourceforge.net">Linux PPTP client project</ulink> has a nice GUI for configuring and managing VPN connections where your Linux system is the PPTP client. This is what I currently use. I am no longer running PoPToP but rather I use the PPTP Server included with XP Professional (see <ulink url="PPTP.htm#ServerBehind">PPTP Server running behind your Firewall</ulink> below).</para> <variablelist> <varlistentry> <term><ulink url="http://pptpclient.sourceforge.net">http://pptpclient.sourceforge.net</ulink></term> <listitem> <para>Everything you need to run a PPTP client.</para> </listitem> </varlistentry> <varlistentry> <term><ulink url="http://www.poptop.org">http://www.poptop.org</ulink></term> <listitem> <para>The 'kernelmod' package can be used to quickly install MPPE into your kernel without rebooting.</para> </listitem> </varlistentry> </variablelist> <para>I am leaving the instructions for building MPPE-enabled kernels and pppd in the text below for those who may wish to obtain the relevant current patches and "roll their own".</para> </section> <section id="ServerFW"> <title>PPTP Server Running on your Firewall</title> <para>I will try to give you an idea of how to set up a PPTP server on your firewall system. This isn't a detailed HOWTO but rather an example of how I have set up a working PPTP server on my own firewall.</para> <para>The steps involved are:</para> <orderedlist> <listitem> <para><xref linkend="PatchPppd" /></para> </listitem> <listitem> <para><xref linkend="PatchKernel" /></para> </listitem> <listitem> <para><xref linkend="Samba" /></para> </listitem> <listitem> <para><xref linkend="ConfigPppd" /></para> </listitem> <listitem> <para><xref linkend="ConfigPptpd" /></para> </listitem> <listitem> <para><xref linkend="ConfigFw" /></para> </listitem> </orderedlist> <section id="PatchPppd"> <title>Patching and building pppd</title> <para>To run pppd on a 2.4 kernel, you need the pppd 2.4.1 or later. The primary site for releases of pppd is <ulink url="ftp://ftp.samba.org/pub/ppp">ftp://ftp.samba.org/pub/ppp</ulink>.</para> <para>You will need the following patches:</para> <simplelist> <member><ulink url="http://www.shorewall.net/pub/shorewall/pptp/ppp-2.4.1-openssl-0.9.6-mppe-patch.gz">http://www.shorewall.net/pub/shorewall/pptp/ppp-2.4.1-openssl-0.9.6-mppe-patch.gz</ulink></member> <member><ulink url="http://www.shorewall.net/pub/shorewall/pptp/ppp-2.4.1-MSCHAPv2-fix.patch.gz">http://www.shorewall.net/pub/shorewall/pptp/ppp-2.4.1-MSCHAPv2-fix.patch.gz</ulink></member> </simplelist> <para>You may also want the following patch if you want to require remote hosts to use encryption:</para> <simplelist> <member><ulink url="ftp://ftp.shorewall.net/pub/shorewall/pptp/require-mppe.diff">ftp://ftp.shorewall.net/pub/shorewall/pptp/require-mppe.diff</ulink></member> </simplelist> <para>Un-tar the pppd source and uncompress the patches into one directory (the patches and the ppp-2.4.1 directory are all in a single parent directory):</para> <programlisting>cd ppp-2.4.1 patch -p1 < ../ppp-2.4.0-openssl-0.9.6-mppe.patch patch -p1 < ../ppp-2.4.1-MSCHAPv2-fix.patch (Optional) patch -p1 < ../require-mppe.diff ./configure make</programlisting> <para>You will need to install the resulting binary on your firewall system. To do that, I NFS mount my source filesystem and use "make install" from the ppp-2.4.1 directory.</para> </section> <section id="PatchKernel"> <title>Patching and building your Kernel</title> <para>You will need one of the following patches depending on your kernel version:</para> <simplelist> <member>http://www.shorewall.net/pub/shorewall/pptp/linux-2.4.4-openssl-0.9.6a-mppe-patch.gz</member> <member>http://www.shorewall/net/pub/shorewall/pptp/linux-2.4.16-openssl-0.9.6b-mppe-patch.gz</member> </simplelist> <para>Uncompress the patch into the same directory where your top-level kernel source is located and:</para> <programlisting>cd <your GNU/Linux source top-level directory> patch -p1 < ../linux-2.4.16-openssl-0.9.6b-mppe.patch</programlisting> <para>Now configure your kernel. Here is my ppp configuration:</para> <graphic fileref="images/ppp.jpg" /> </section> <section id="Samba"> <title>Configuring Samba</title> <para>You will need a WINS server (Samba configured to run as a WINS server is fine). Global section from /etc/samba/smb.conf on my WINS server (192.168.1.3) is:</para> <programlisting>[global] workgroup = TDM-NSTOP netbios name = WOOKIE server string = GNU/Linux Box encrypt passwords = Yes log file = /var/log/samba/%m.log max log size = 0 socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192 os level = 65 domain master = True preferred master = True dns proxy = No wins support = Yes printing = lprng [homes] comment = Home Directories valid users = %S read only = No create mask = 0664 directory mask = 0775 [printers] comment = All Printers path = /var/spool/samba printable = Yes</programlisting> </section> <section id="ConfigPppd"> <title>Configuring pppd</title> <para>Here is a copy of my /etc/ppp/options.poptop file:</para> <programlisting>ipparam PoPToP lock mtu 1490 mru 1490 ms-wins 192.168.1.3 ms-dns 206.124.146.177 multilink proxyarp auth +chap +chapms +chapms-v2 ipcp-accept-local ipcp-accept-remote lcp-echo-failure 30 lcp-echo-interval 5 deflate 0 mppe-128 mppe-stateless require-mppe require-mppe-stateless</programlisting> <note> <itemizedlist> <listitem> <para>System 192.168.1.3 acts as a WINS server so I have included that IP as the 'ms-wins' value.</para> </listitem> <listitem> <para>I have pointed the remote clients at my DNS server -- it has external address 206.124.146.177.</para> </listitem> <listitem> <para>I am requiring 128-bit stateless compression (my kernel is built with the 'require-mppe.diff' patch mentioned above.</para> </listitem> </itemizedlist> </note> <para>Here's my /etc/ppp/chap-secrets:</para> <programlisting>Secrets for authentication using CHAP # client server secret IP addresses CPQTDM\\TEastep * <shhhhhh> 192.168.1.7 TEastep * <shhhhhh> 192.168.1.7</programlisting> <para>I am the only user who connects to the server but I may connect either with or without a domain being specified. The system I connect from is my laptop so I give it the same IP address when tunneled in at it has when I use its wireless LAN card around the house.</para> <para>You will also want the following in /etc/modules.conf:</para> <programlisting>alias ppp-compress-18 ppp_mppe alias ppp-compress-21 bsd_comp alias ppp-compress-24 ppp_deflate alias ppp-compress-26 ppp_deflate</programlisting> </section> <section id="ConfigPptpd"> <title>Configuring pptpd</title> <para>PoPTop (pptpd) is available from <ulink url="http://poptop.lineo.com/">http://poptop.lineo.com/</ulink>.</para> <para>Here is a copy of my /etc/pptpd.conf file:</para> <programlisting>option /etc/ppp/options.poptop speed 115200 localip 192.168.1.254 remoteip 192.168.1.33-38</programlisting> <note> <itemizedlist> <listitem> <para>I specify the /etc/ppp/options.poptop file as my ppp options file (I have several).</para> </listitem> <listitem> <para>The local IP is the same as my internal interface's (192.168.1.254).</para> </listitem> <listitem> <para>I have assigned a remote IP range that overlaps my local network. This, together with 'proxyarp' in my /etc/ppp/options.poptop file make the remote hosts look like they are part of the local subnetwork.</para> </listitem> </itemizedlist> </note> <para>I use this file to start/stop pptpd -- I have this in /etc/init.d/pptpd:</para> <programlisting>#!/bin/sh # # /etc/rc.d/init.d/pptpd # # chkconfig: 5 12 85 # description: control pptp server # case "$1" in start) echo 1 > /proc/sys/net/ipv4/ip_forward modprobe ppp_async modprobe ppp_generic modprobe ppp_mppe modprobe slhc if /usr/local/sbin/pptpd; then touch /var/lock/subsys/pptpd fi ;; stop) killall pptpd rm -f /var/lock/subsys/pptpd ;; restart) killall pptpd if /usr/local/sbin/pptpd; then touch /var/lock/subsys/pptpd fi ;; status) ifconfig ;; *) echo "Usage: $0 {start|stop|restart|status}" ;; esac</programlisting> </section> <section id="ConfigFw"> <title>Configuring Shorewall</title> <section> <title>Basic Setup</title> <para>Here' a basic setup that treats your remote users as if they were part of your <emphasis role="bold">loc</emphasis> zone. Note that if your primary internet connection uses ppp0, then be sure that <emphasis role="bold">loc</emphasis> follows <emphasis role="bold">net</emphasis> in /etc/shorewall/zones.</para> <table> <title>/etc/shorewall/tunnels</title> <tgroup cols="4"> <thead> <row> <entry align="center">TYPE</entry> <entry align="center">ZONE</entry> <entry align="center">GATEWAY</entry> <entry align="center">GATEWAY ZONE</entry> </row> </thead> <tbody> <row> <entry>pptpserver</entry> <entry>net</entry> <entry>0.0.0.0/0</entry> <entry></entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/interfaces</title> <tgroup cols="4"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">INTERFACE</entry> <entry align="center">BROADCAST</entry> <entry align="center">OPTIONS</entry> </row> </thead> <tbody> <row> <entry>loc</entry> <entry>ppp+</entry> <entry>-</entry> <entry></entry> </row> </tbody> </tgroup> </table> </section> <section> <title>Remote Users in a Separate Zone</title> <para>If you want to place your remote users in their own zone so that you can control connections between these users and the local network, follow this example. Note that if your primary internet connection uses ppp0 then be sure that <emphasis role="bold">vpn</emphasis> follows <emphasis role="bold">net</emphasis> in /etc/shorewall/zones as shown below.</para> <table> <title>/etc/shorewall/tunnels</title> <tgroup cols="4"> <thead> <row> <entry align="center">TYPE</entry> <entry align="center">ZONE</entry> <entry align="center">GATEWAY</entry> <entry align="center">GATEWAY ZONE</entry> </row> </thead> <tbody> <row> <entry>pptpserver</entry> <entry>net</entry> <entry>0.0.0.0/0</entry> <entry></entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/zones</title> <tgroup cols="3"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">DISPLAY</entry> <entry align="center">COMMENTS</entry> </row> </thead> <tbody> <row> <entry>net</entry> <entry>Internet</entry> <entry>The Internet</entry> </row> <row> <entry>loc</entry> <entry>Local</entry> <entry>Local Network</entry> </row> <row> <entry>vpn</entry> <entry>VPN</entry> <entry>Remote Users</entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/interfaces</title> <tgroup cols="4"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">INTERFACE</entry> <entry align="center">BROADCAST</entry> <entry align="center">OPTIONS</entry> </row> </thead> <tbody> <row> <entry>net</entry> <entry>eth0</entry> <entry>206.124.146.255</entry> <entry>norfc1918</entry> </row> <row> <entry>loc</entry> <entry>eth2</entry> <entry>192.168.10.255</entry> <entry></entry> </row> <row> <entry>vpn</entry> <entry>ppp+</entry> <entry>-</entry> <entry></entry> </row> </tbody> </tgroup> </table> <para>Your policies and rules may now be configured for traffic to/from the <emphasis role="bold">vpn</emphasis> zone.</para> </section> <section> <title>Multiple Remote Networks</title> <para>Often there will be situations where you want multiple connections from remote networks with these networks having different firewalling requirements.<graphic fileref="images/MultiPPTP.png" /></para> <para>Here's how you configure this in Shorewall. Note that if your primary internet connection uses ppp0 then be sure that the <emphasis role="bold">vpn{1-3}</emphasis> zones follows <emphasis role="bold">net</emphasis> in /etc/shorewall/zones as shown below.</para> <table> <title>/etc/shorewall/tunnels</title> <tgroup cols="4"> <thead> <row> <entry align="center">TYPE</entry> <entry align="center">ZONE</entry> <entry align="center">GATEWAY</entry> <entry align="center">GATEWAY ZONE</entry> </row> </thead> <tbody> <row> <entry>pptpserver</entry> <entry>net</entry> <entry>0.0.0.0/0</entry> <entry></entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/zones</title> <tgroup cols="3"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">DISPLAY</entry> <entry align="center">COMMENTS</entry> </row> </thead> <tbody> <row> <entry>net</entry> <entry>Internet</entry> <entry>The Internet</entry> </row> <row> <entry>loc</entry> <entry>Local</entry> <entry>Local Network</entry> </row> <row> <entry>vpn1</entry> <entry>Remote1</entry> <entry>Remote Network 1</entry> </row> <row> <entry>vpn2</entry> <entry>Remote2</entry> <entry>Remote Network 2</entry> </row> <row> <entry>vpn3</entry> <entry>Remote3</entry> <entry>Remote Network 3</entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/interfaces</title> <tgroup cols="4"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">INTERFACE</entry> <entry align="center">BROADCAST</entry> <entry align="center">OPTIONS</entry> </row> </thead> <tbody> <row> <entry>net</entry> <entry>eth0</entry> <entry>206.124.146.255</entry> <entry>norfc1918</entry> </row> <row> <entry>loc</entry> <entry>eth2</entry> <entry>192.168.10.255</entry> <entry></entry> </row> <row> <entry>-</entry> <entry>ppp+</entry> <entry>-</entry> <entry></entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/hosts</title> <tgroup cols="3"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">HOST(S)</entry> <entry align="center">OPTIONS</entry> </row> </thead> <tbody> <row> <entry>vpn1</entry> <entry>ppp+:192.168.1.0/24</entry> <entry></entry> </row> <row> <entry>vpn2</entry> <entry>ppp+:192.168.2.0/24</entry> <entry></entry> </row> <row> <entry>vpn3</entry> <entry>ppp+:192.168.3.0/24</entry> <entry></entry> </row> </tbody> </tgroup> </table> <para>Your policies and rules can now be configured using separate zones (vpn1, vpn2, and vpn3) for the three remote network.</para> </section> </section> </section> <section id="ServerBehind"> <title>PPTP Server Running Behind your Firewall</title> <para>If you have a single external IP address, add the following to your /etc/shorewall/rules file:</para> <table> <title>/etc/shorewall/rules</title> <tgroup cols="7"> <thead> <row> <entry align="center">ACTION</entry> <entry align="center">SOURCE</entry> <entry>DEST</entry> <entry>PROTO</entry> <entry>DEST PORT(S)</entry> <entry>SOURCE PORT(S)</entry> <entry>ORIGINAL DEST</entry> </row> </thead> <tbody> <row> <entry>DNAT</entry> <entry>net</entry> <entry>loc:<<emphasis>server address</emphasis>></entry> <entry>tcp</entry> <entry>1723</entry> <entry></entry> <entry></entry> </row> <row> <entry>DNAT</entry> <entry>net</entry> <entry>loc:<<emphasis>server address</emphasis>></entry> <entry>47</entry> <entry>-</entry> <entry></entry> <entry></entry> </row> </tbody> </tgroup> </table> <para>If you have multiple external IP address and you want to forward a single <<emphasis>external address</emphasis>>, add the following to your /etc/shorewall/rules file:</para> <table> <title>/etc/shorewall/rules</title> <tgroup cols="7"> <thead> <row> <entry align="center">ACTION</entry> <entry align="center">SOURCE</entry> <entry>DEST</entry> <entry>PROTO</entry> <entry>DEST PORT(S)</entry> <entry>SOURCE PORT(S)</entry> <entry>ORIGINAL DEST</entry> </row> </thead> <tbody> <row> <entry>DNAT</entry> <entry>net</entry> <entry>loc:<<emphasis>server address</emphasis>></entry> <entry>tcp</entry> <entry>1723</entry> <entry>-</entry> <entry><<emphasis>external address</emphasis>></entry> </row> <row> <entry>DNAT</entry> <entry>net</entry> <entry>loc:<<emphasis>server address</emphasis>></entry> <entry>47</entry> <entry>-</entry> <entry>-</entry> <entry><<emphasis>external address</emphasis>></entry> </row> </tbody> </tgroup> </table> </section> <section id="ClientsBehind"> <title>PPTP Clients Running Behind your Firewall</title> <para>You shouldn't have to take any special action for this case unless you wish to connect multiple clients to the same external server. In that case, you will need to follow the instructions at <ulink url="http://www.impsec.org/linux/masquerade/ip_masq_vpn.html">http://www.impsec.org/linux/masquerade/ip_masq_vpn.html</ulink>. I recommend that you also add these three lines to your /etc/shorewall/modules file:</para> <programlisting>loadmodule ip_conntrack_proto_gre loadmodule ip_conntrack_pptp loadmodule ip_nat_pptp</programlisting> <para>For LEAF/Bering users, the 2.4.20 kernel as already been patched as described at the URL above and the three modules are included in the Bering 1.2 modules tarball.</para> </section> <section id="ClientFW"> <title>PPTP Client Running on your Firewall</title> <para>The PPTP GNU/Linux client is available at <ulink url="http://sourceforge.net/projects/pptpclient/">http://sourceforge.net/projects/pptpclient/</ulink>. Rather than use the configuration script that comes with the client, I built my own. I also build my own kernel <link linkend="PatchKernel">as described above</link> rather than using the mppe package that is available with the client. My /etc/ppp/options file is mostly unchanged from what came with the client (see below).</para> <para>The key elements of this setup are as follows:</para> <orderedlist> <listitem> <para>Define a zone for the remote network accessed via PPTP.</para> </listitem> <listitem> <para>Associate that zone with a ppp interface.</para> </listitem> <listitem> <para>Define rules for PPTP traffic to/from the firewall.</para> </listitem> <listitem> <para>Define rules for traffic two and from the remote zone.</para> </listitem> </orderedlist> <para>Here are examples from my setup:</para> <table> <title>/etc/shorewall/zones</title> <tgroup cols="3"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">DISPLAY</entry> <entry align="center">COMMENTS</entry> </row> </thead> <tbody> <row> <entry>cpq</entry> <entry>Compaq</entry> <entry>Compaq Intranet</entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/interfaces</title> <tgroup cols="4"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">INTERFACE</entry> <entry align="center">BROADCAST</entry> <entry align="center">OPTIONS</entry> </row> </thead> <tbody> <row> <entry>-</entry> <entry>ppp+</entry> <entry></entry> <entry></entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/hosts</title> <tgroup cols="3"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">HOST(S)</entry> <entry align="center">OPTIONS</entry> </row> </thead> <tbody> <row> <entry>-</entry> <entry>ppp+:!192.168.1.0/24</entry> <entry></entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/rules (For Shorewall versions up to and including 1.3.9b)</title> <tgroup cols="7"> <thead> <row> <entry align="center">ACTION</entry> <entry align="center">SOURCE</entry> <entry align="center">DEST</entry> <entry align="center">PROTO</entry> <entry align="center">DEST PORT(S)</entry> <entry align="center">SOURCE PORT(S)</entry> <entry align="center">ORIGINAL DEST</entry> </row> </thead> <tbody> <row> <entry>ACCEPT</entry> <entry>fw</entry> <entry>net</entry> <entry>tcp</entry> <entry>1723</entry> <entry></entry> <entry></entry> </row> <row> <entry>ACCEPT</entry> <entry>fw</entry> <entry>net</entry> <entry>47</entry> <entry>-</entry> <entry></entry> <entry></entry> </row> </tbody> </tgroup> </table> <table> <title>/etc/shorewall/tunnels (For Shorewall versions 1.3.10 and later)</title> <tgroup cols="4"> <thead> <row> <entry align="center">TYPE</entry> <entry align="center">ZONE</entry> <entry align="center">GATEWAY</entry> <entry align="center">GATEWAY ZONE</entry> </row> </thead> <tbody> <row> <entry>pptpclient</entry> <entry>net</entry> <entry>0.0.0.0/0</entry> <entry></entry> </row> </tbody> </tgroup> </table> <para>I use the combination of interface and hosts file to define the 'cpq' zone because I also run a PPTP server on my firewall (see above). Using this technique allows me to distinguish clients of my own PPTP server from arbitrary hosts at Compaq; I assign addresses in 192.168.1.0/24 to my PPTP clients and Compaq doesn't use that RFC1918 Class C subnet.</para> <para>I use this script in /etc/init.d to control the client. The reason that I disable ECN when connecting is that the Compaq tunnel servers don't do ECN yet and reject the initial TCP connection request if I enable ECN :-(</para> <programlisting>#!/bin/sh # # /etc/rc.d/init.d/pptp # # chkconfig: 5 60 85 # description: PPTP Link Control # NAME="Tandem" ADDRESS=tunnel-tandem.compaq.com USER='Tandem\tommy' ECN=0 DEBUG= start_pptp() { echo $ECN > /proc/sys/net/ipv4/tcp_ecn if /usr/sbin/pptp $ADDRESS user $USER noauth $DEBUG; then touch /var/lock/subsys/pptp echo "PPTP Connection to $NAME Started" fi } stop_pptp() { if killall /usr/sbin/pptp 2> /dev/null; then echo "Stopped pptp" else rm -f /var/run/pptp/* fi # if killall pppd; then # echo "Stopped pppd" # fi rm -f /var/lock/subsys/pptp echo 1 > /proc/sys/net/ipv4/tcp_ecn } case "$1" in start) echo "Starting PPTP Connection to ${NAME}..." start_pptp ;; stop) echo "Stopping $NAME PPTP Connection..." stop_pptp ;; restart) echo "Restarting $NAME PPTP Connection..." stop_pptp start_pptp ;; status) ifconfig ;; *) echo "Usage: $0 {start|stop|restart|status}" ;; esac</programlisting> <para>Here's my /etc/ppp/options file:</para> <programlisting># # Identify this connection # ipparam Compaq # # Lock the port # lock # # We don't need the tunnel server to authenticate itself # noauth +chap +chapms +chapms-v2 multilink mrru 1614 # # Turn off transmission protocols we know won't be used # nobsdcomp nodeflate # # We want MPPE # mppe-128 mppe-stateless # # We want a sane mtu/mru # mtu 1000 mru 1000 # # Time this thing out of it goes poof # lcp-echo-failure 10 lcp-echo-interval 10</programlisting> <para>My /etc/ppp/ip-up.local file sets up the routes that I need to route Compaq traffic through the PPTP tunnel:</para> <programlisting>#/bin/sh case $6 in Compaq) route add -net 16.0.0.0 netmask 255.0.0.0 gw $5 $1 route add -net 130.252.0.0 netmask 255.255.0.0 gw $5 $1 route add -net 131.124.0.0 netmask 255.255.0.0 gw $5 $1 ... ;; esac</programlisting> <para>Finally, I run the following script every five minutes under crond to restart the tunnel if it fails:</para> <programlisting>#!/bin/sh restart_pptp() { /sbin/service pptp stop sleep 10 if /sbin/service pptp start; then /usr/bin/logger "PPTP Restarted" fi } if [ -n "`ps ax | grep /usr/sbin/pptp | grep -v grep`" ]; then exit 0 fi echo "Attempting to restart PPTP" restart_pptp > /dev/null 2>&1 &</programlisting> <para><ulink url="ftp://ftp.shorewall.net/pub/shorewall/misc/Vonau">Here's a scriptand corresponding ip-up.local</ulink> from Jerry Vonau <email>jvonau@home.com</email> that controls two PPTP connections.</para> </section> <section id="PPTP_ADSL"> <title>PPTP Client running on your Firewall with PPTP Server in an ADSL Modem</title> <para>Some ADSL systems in Europe (most notably in Austria) feature a PPTP server built into an ADSL "Modem". In this setup, an ethernet interface is dedicated to supporting the PPTP tunnel between the firewall and the "Modem" while the actual internet access is through PPTP (interface ppp0). If you have this type of setup, you need to modify the sample configuration that you downloaded as described in this section. <emphasis role="bold">These changes are in addition to those described in the <ulink url="shorewall_quickstart_guide.htm">QuickStart Guides</ulink>.</emphasis></para> <para>Lets assume the following:</para> <itemizedlist> <listitem> <para>ADSL Modem connected through eth0</para> </listitem> <listitem> <para>Modem IP address = 192.168.1.1</para> </listitem> <listitem> <para>eth0 IP address = 192.168.1.2</para> </listitem> </itemizedlist> <para>The changes you need to make are as follows:</para> <orderedlist> <listitem> <para>Add this entry to /etc/shorewall/zones:</para> <table> <title>/etc/shorewall/zones</title> <tgroup cols="3"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">DISPLAY</entry> <entry align="center">COMMENTS</entry> </row> </thead> <tbody> <row> <entry>modem</entry> <entry>Modem</entry> <entry>ADSL Modem</entry> </row> </tbody> </tgroup> </table> <para>That entry defines a new zone called 'modem' which will contain only your ADSL modem.</para> </listitem> <listitem> <para>Add the following entry to /etc/shorewall/interfaces:</para> <table> <title>/etc/shorewall/interfaces</title> <tgroup cols="4"> <thead> <row> <entry align="center">ZONE</entry> <entry align="center">INTERFACE</entry> <entry align="center">BROADCAST</entry> <entry align="center">OPTIONS</entry> </row> </thead> <tbody> <row> <entry>modem</entry> <entry>eth0</entry> <entry>192.168.1.255</entry> <entry>dhcp</entry> </row> </tbody> </tgroup> </table> <para>You will of course modify the 'net' entry in /etc/shorewall/interfaces to specify 'ppp0' as the interface as described in the QuickStart Guide corresponding to your setup.</para> </listitem> <listitem> <para>Add the following to /etc/shorewall/tunnels:</para> <table> <title>/etc/shorewall/tunnels</title> <tgroup cols="4"> <thead> <row> <entry align="center">TYPE</entry> <entry align="center">ZONE</entry> <entry align="center">GATEWAY</entry> <entry align="center">GATEWAY ZONE</entry> </row> </thead> <tbody> <row> <entry>pptpclient</entry> <entry>modem</entry> <entry>192.168.1.1</entry> <entry></entry> </row> </tbody> </tgroup> </table> <para>That entry allows a PPTP tunnel to be established between your Shorewall system and the PPTP server in the modem.</para> </listitem> </orderedlist> </section> </article>