[pptp-server] Clogged Tunnel!

[Luke Myers]

Hi Folks,

I have a three exellent looking PPTP tunnels between one Redhat 7.0 box and
three different Win98 clients.  However, one tunnel will not pass any data,
not even a ping! I am using:

-- PoPToP v1.0.0
-- Linux 2.2.16-22
-- pppd 2.3.11
-- 128bit stateless encryption
-- 128bit Dial-up Networking upgrades
-- Windows 98

Following is the log output for a good connection:

Mar 21 21:40:42 ds pptpd[30394]: CTRL: Client 208.164.103.206 control
connection started
Mar 21 21:40:45 ds pptpd[30394]: CTRL: Starting call (launching pppd,
opening GRE)
Mar 21 21:40:45 ds pppd[30395]: pppd 2.3.11 started by root, uid 0
Mar 21 21:40:45 ds pppd[30395]: Using interface ppp2
Mar 21 21:40:45 ds pppd[30395]: Connect: ppp2 <--> /dev/pts/1
Mar 21 21:40:46 ds pppd[30395]: MSCHAP-v2 peer authentication succeeded for
OUR-WORKGROUP\\luke
Mar 21 21:40:47 ds pppd[30395]: Cannot determine ethernet address for proxy
ARP
Mar 21 21:40:47 ds pppd[30395]: local  IP address 192.168.1.1
Mar 21 21:40:47 ds pppd[30395]: remote IP address 192.168.1.5
Mar 21 21:40:47 ds pppd[30395]: MPPE 128 bit, stateless compression enabled
Mar 21 21:44:45 ds pppd[29457]: LCP terminated by peer
Mar 21 21:44:47 ds pptpd[29456]: CTRL: Error with select(), quitting
Mar 21 21:44:47 ds pptpd[29456]: CTRL: Client 24.48.231.141 control
connection finished
Mar 21 21:44:47 ds pppd[29457]: Modem hangup
Mar 21 21:44:47 ds pppd[29457]: Connection terminated.
Mar 21 21:44:47 ds pppd[29457]: Connect time 286.0 minutes.
Mar 21 21:44:47 ds pppd[29457]: Sent 4307228 bytes, received 1957577 bytes.
Mar 21 21:44:47 ds pppd[29457]: Exit.


Following is the first part of the log output for a connection that looks
sucessful but cannot move any data:

Mar 21 20:32:21 ds pptpd[30114]: CTRL: Client 24.48.139.165 control
connection started
Mar 21 20:32:21 ds pptpd[30114]: CTRL: Starting call (launching pppd,
opening GRE)
Mar 21 20:32:21 ds pppd[30115]: pppd 2.3.11 started by root, uid 0
Mar 21 20:32:21 ds pppd[30115]: Using interface ppp0
Mar 21 20:32:21 ds pppd[30115]: Connect: ppp0 <--> /dev/pts/0
Mar 21 20:32:22 ds pppd[30115]: MSCHAP-v2 peer authentication succeeded for
our-workgroup\\ldke$%^*
Mar 21 20:32:22 ds pppd[30115]: Cannot determine ethernet address for proxy
ARP
Mar 21 20:32:22 ds pppd[30115]: local  IP address 192.168.1.1
Mar 21 20:32:22 ds pppd[30115]: remote IP address 192.168.1.3
Mar 21 20:32:22 ds pppd[30115]: MPPE 128 bit, stateless compression enabled

Here is my /etc/ppp/options.pptp file:

auth
lock
debug
proxyarp
+chap
+chapms
+chapms-v2
mppe-40
mppe-128
mppe-stateless
ms-wins 192.168.1.1

Here are the essentials from my /etc/pptpd.conf file:

option /etc/ppp/options.pptp
debug
localip 192.168.1.1
remoteip 192.168.1.2-254

This problem is mystifying because:

I can ping fine directly between the affected Win98 box and the Linux
server,

Win98 connection shows nothing wrong or abnormal about the connection,

The Linux log files show no difference between the good connections and the
bad connection, and

Disabling compression and encryption though Windows does not help.