[pptp-server] pptp behind a Pipeline 75

[Support]

I am having problems with one of my remote offices. We have an ISDN
connection, and a pipeline 75 router. The pipeline is running the latest
software to allow a single pptp (tunnel server), and the internal ip address
of the linux box (eth0) has been entered.

Our ISP is a dialup, so we are only assigned a single dynamic address. The
ethernet side of the router is connected directly to a linux box (eth0: ext)
that is running the firewall code and ip_pptp_masq.

What I have noticed is that one client can connect to our pptp server, ping
any of the addresses on the network and all is well. Once a second one
connects to the same ip address of the server, neither connections work,
although they authenticate, and succesfully obtain an ip address.

The pptp server is running version 1.0.0 PoPToP.

Any suggestions will be greatly appreciated.

Thank You
Ronnie

/------------------\
| public ip        |
| linux computer   |
| pptp server      |
\------------------/
      |
      |
   *internet*
      |
      |------------------other remote offices
      |
      |(isdn)
/-----------------\
| DHCP Public wan0|
|  Pipeline 75    |
| 192.168.5.1 eth |
\-----------------/
      |
      |
      |
/-----------------\
| 192.168.5.2 eth0|
|  Linux RH 6.2   |
| 192.168.1.1 eth1|
\-----------------/
      |
192.168.1/24  (internal computers)