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<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>Hi List,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>This is an update for anyone that has been attempting
to get a PPTP VPN working using PopTop with more than one simultaneous connection
from an external source to a PPTP VPN behind a router that is NATing
connections through. I assume that whoever is setting this up has some
general knowledge of linux and how to compile a kernel. I also make the
assumption that you already have a PPTP server up and running but are requiring
more than one simultaneous connection. I also offer no warranties or take
on any responsibility on whether or not this breaks your system and causes damage
of any kind.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>With that said, I used the most recent kernel
(2.6.18.3) and used all the default settings and added in all (except the experimental)
iptables modules. I also added in PPP MPPE support (even though it is
experimental). To make things easier on myself I compiled the kernel as a
binary RPM package since the distro that I am using uses RPMs.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>After installing the new kernel I made modifications
to my boot loader (in my case grub) to use the new kernel and then rebooted the
system.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>I used the following IPTables rules:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>iptables –t nat –A POSTROUTING –j MASQUERADE
– (Very general masquerading – not recommended and should be tied
down to specific subnets)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>iptables –A INPUT –p tcp –dport 1723
–j ACCEPT (Accept inbound PPTP connections)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>iptables –A INPUT –p gre –j ACCEPT
(Accept inbound GRE connections)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>iptables –A OUTPUT –p gre –j ACCEPT
(Accept outbound GRE connections)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>I executed the command:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>service iptables save<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>to save my newly added iptables rules.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>I then edited /etc/rc.local and added in the
following lines<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>modprobe ip_nat_pptp<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>modprobe ip_conntrack_pptp<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>Which loads the additional modules needed for PPTP NAT
connections and finally rebooted the system once more to make sure everything
starts up as expected.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-NZ style='font-size:
10.0pt;font-family:Arial'>If you have any problems please mail them to the list
and I will see if I can be of some assistance.<o:p></o:p></span></font></p>
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