pptp vpn logon problems

hepp · 07-20-2005, 10:14 AM

I have an ubuntu box running poptop. Configuration seems okey, because I can log on as long as I log on from another machine in the network - but when I try to connect to the vpn externally (tried from 3 different computers/places) I get a 691 error (specified port is not connected) after it has made the connection and tries to verify username and password.

From the logs on the ubuntu machine it looks like the LCP Config request never reaches the client - or that the reply never reaches the server. So I'm guessing it might be a routing problem since the ubuntu is behind an SMC router. I have opened port 1732 and 49 and tried to put it in DMZ, but I still can't logon externally.

Code:

Jul 20 17:08:26 localhost pptpd[6373]: CTRL: Client 212.33.xx.xx control connection started
Jul 20 17:08:26 localhost pptpd[6373]: CTRL: Starting call (launching pppd, opening GRE)
Jul 20 17:08:26 localhost pppd[6374]: Plugin /usr/lib/pptpd/pptpd-logwtmp.so loaded.
Jul 20 17:08:26 localhost pppd[6374]: pptpd-logwtmp: $Version$
Jul 20 17:08:26 localhost pppd[6374]: pppd 2.4.2 started by root, uid 0
Jul 20 17:08:26 localhost pppd[6374]: using channel 18
Jul 20 17:08:26 localhost pppd[6374]: Using interface ppp0
Jul 20 17:08:26 localhost pppd[6374]: Connect: ppp0 <--> /dev/pts/1
Jul 20 17:08:26 localhost pppd[6374]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth chap MS-v2> <magic 0xba13411d> <pcomp> <accomp>]
Jul 20 17:08:26 localhost pptpd[6373]: GRE: Bad checksum from pppd.
Jul 20 17:08:29 localhost pppd[6374]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth chap MS-v2> <magic 0xba13411d> <pcomp> <accomp>]
Jul 20 17:08:53 localhost last message repeated 8 times
Jul 20 17:08:56 localhost pppd[6374]: LCP: timeout sending Config-Requests
Jul 20 17:08:56 localhost pppd[6374]: Connection terminated.
Jul 20 17:08:56 localhost pppd[6374]: Exit.
Jul 20 17:08:56 localhost pptpd[6373]: GRE: read(fd=4,buffer=804e6c0,len=8196) from PTY failed: status = -1 error = Input/output error, usually caused by unexpected termination of pppd, check option syntax and pppd logs
Jul 20 17:08:56 localhost pptpd[6373]: CTRL: PTY read or GRE write failed (pty,gre)=(4,5)
Jul 20 17:08:56 localhost pptpd[6373]: CTRL: Reaping child PPP[6374]
Jul 20 17:08:56 localhost pptpd[6373]: CTRL: Client 212.33.xx.xx control connection finished

Are there any changes I can make to my router config, or are there any errors on the setup?

michaelk · 07-20-2005, 10:53 AM

Check the pppd logs
poptop uses protocol 49 (gre) which is different then TCP 49.
What client/os are you using to connect to the poptop box.
post your options.pptp file

hepp · 07-20-2005, 11:02 AM

Tried both windows and linux to connect.
The linux clients behaves like the the server, sending LCP Config request without getting a reply (when connecting to the external ip, if it's in the network and can connect to the internal ip it works just fine):

Connect: ppp0 <--> /dev/pts/1
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x499f6437> <pcomp> <accomp>]
--- repeated X times ---
LCP: timeout sending Config-Requests

My /etc/ppp/options file

Code:

ms-dns 212.33.139.1
ms-dns 212.33.139.2
ms-wins 192.168.123.2
asyncmap 0
auth
crtscts
lock
hide-password
modem
kdebug 1
proxyarp
lcp-echo-interval 30
lcp-echo-failure 4
noipx

/etc/ppp/pptpd-options

Code:

name pptpd
refuse-pap
refuse-chap
refuse-mschap
require-mschap-v2
require-mppe-128
ms-dns 212.33.139.1
ms-dns 212.33.139.2
ms-wins 192.168.123.2
proxyarp
nodefaultroute
debug
lock
nobsdcomp