[pptp-server] NAT?

[Marc Charbonneau]

Your NAT doesn't seem to handle the GRE protocol correctly.

What is you NAT ? if it's a Linux-box, you have to apply a patch to your
kernel for it to handle-it correctly.

HTH
----- Original Message -----
From: <pptplist at mail.doris.cc>
To: <pptp-server at lists.schulte.org>
Sent: Tuesday, March 27, 2001 10:10 AM
Subject: [pptp-server] NAT?


> I am running pptp on a linux box and connecting with a win2000 client over
> the internet and having problems with NAT.
>
> Here is what I have in my options file.
>
> lock
> auth
> debug
> proxyarp
> require-chap
> +chap
> +chapms
> +chapms-v2
> mppe-40
> mppe-128
> mppe-stateless
> name pptpd
>
> When my Windows 2000 Client connects from a static IP address everything
> works fine.  When my Windows 2000 client tries to connect from a NAT'd
> connection, I get a error 619, specified port is not connected.
>
> Here is what I see in my log files.
>
> Mar 27 10:02:01 mail pptpd[4027]: CTRL: Client xxx.xxx.xxx.xxx control
connection started
> Mar 27 10:02:01 mail pptpd[4027]: CTRL: Starting call (launching pppd,
opening GRE)
> Mar 27 10:02:01 mail kernel: CSLIP: code copyright 1989 Regents of the
> University of California
> Mar 27 10:02:01 mail kernel: PPP: version 2.3.7 (demand dialling)
> Mar 27 10:02:01 mail kernel: PPP line discipline registered.
> Mar 27 10:02:01 mail kernel: registered device ppp0
> Mar 27 10:02:01 mail pppd[4028]: pppd 2.3.11 started by root, uid 0
> Mar 27 10:02:01 mail pppd[4028]: Using interface ppp0
> Mar 27 10:02:01 mail pppd[4028]: Connect: ppp0 <--> /dev/pts/3
> Mar 27 10:02:01 mail pptpd[4027]: GRE: Discarding duplicate packet
> Mar 27 10:02:31 mail pppd[4028]: LCP: timeout sending Config-Requests
> Mar 27 10:02:31 mail pppd[4028]: Connection terminated.
> Mar 27 10:02:31 mail pppd[4028]: Exit.
> Mar 27 10:02:31 mail pptpd[4027]: GRE: read(fd=5,buffer=804d8c0,len=8196)
> from PTY failed: status = -1 error = Input/output error
> Mar 27 10:02:31 mail pptpd[4027]: CTRL: PTY read or GRE write failed
(pty,gre)=(5,6)
> Mar 27 10:02:31 mail pptpd[4027]: CTRL: Client xxx.xxx.xxx.xxx control
connection finished
>
> I have the following set up in my ipchains table
>
> ipchains -A forward -i eth0 -s 192.168.100.0/24 -d 192.168.100.0/24 -j
MASQ
> ipchains -A output -s 192.168.100.0/24 -d 192.168.100.0/24 -j ACCEPT
> ipchains -A input -s 192.168.100.0/24 -d 192.168.100.0/24 -j ACCEPT
>
> I have this set up in pptp.conf
>
> localip 192.168.100.210-214
> remoteip 192.168.100.215-218
>
>
> Everything seems to work when the client has a static IP, just not when
> NAT'd.  Any ideas?  I know I am missing something somewhere.
>
> Thanks,
>
> Dustin Doris
>
>
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