Hi all.
I'm using poptop vpn server together with free radius and mysql for authentication and accounting. Due to increased load of main servers, it was necessary to install several new pptpds.
Since i don't want to change settings on every client pc , i've decided to do port forwarding, so clients can be automaticly redirected to the new VPN servers. Connection between client and pptpd is established but radius server does not "see" the request for some reason (i'm using radiusd -X), so auth cannot be processed,client hangs on "Verifying username and password" and eventually disconnects with error 619. At the same time wnen connection is made directly to the server (without dnat) everyting works just fine.
Here is the info from syslog, but i think that these errors resulted from pppd, because it is unable to complete the request.

Dec 15 12:24:14 oborishte pppd[10551]: LCP: timeout sending Config-Requests
Dec 15 12:24:14 oborishte pppd[10551]: tcflush failed: Bad file descriptor
Dec 15 12:24:14 oborishte pppd[10551]: tcsetattr: Invalid argument (line 1001)
Dec 15 12:24:14 oborishte pptpd[10550]: GRE: read(fd=6,buffer=804e780,len=8196) from PTY failed: status = -1 error = Input/out
put error, usually caused by unexpected termination of pppd, check option syntax and pppd logs
Dec 15 12:24:14 oborishte pptpd[10550]: CTRL: PTY read or GRE write failed (pty,gre)=(6,7)


Here is my options.pptpd file

cat /etc/ppp/options.pptpd
name *
lock
mtu 1400
mru 1400
proxyarp
ipcp-accept-local
ipcp-accept-remote
lcp-echo-failure 30
lcp-echo-interval 5
deflate 0
require-mschap-v2
require-chap
#nomppe
#nomppc

plugin radius.so

ms-dns some dns
ms-dns some dns
ms-dns some dns

I'm curtently using
freeradius-1.0.5.tar.gz ppp-2.4.3.tar.gz pptpd-1.2.3.tar.gz radiusclient-0.3.2.tar.gz on Slackware 10.0 kernel 2.4.26

Any ideas will be appreciated since i'm completely stuck on this.

Nobody ever done this?
Here are my iptables rules

iptables -t nat -A PREROUTING -i eth2 -s client.network -d old.vpn.server -p tcp --dport 1723 -j DNAT --to-destination new.vpn.server:1723

iptables -t nat -A PREROUTING -i eth2 -p gre -j DNAT --to new.vnp.server

...or maybe pppd is parsing wrong arguments to pptpd because of the GRE tunnel?

Try changing "-p gre" to "-p 47", only thing I could think of. Though I'm told "gre" or "GRE" should work. Kind of a longshot.



dan

I've already tried with -p 47 with the same result. I gave up and the only thing that continuing to bother me now is...why?
Hope some day i'll get answer to my question and thank you for your help anyway.

I hope you do too. I have tried at various times to set up a pptp vpn server with only very limited success. Mysterious gremlins...

If you find an answer please post back.



dan