[pptp-server] how to access subnet?

[ybzhg at sina.com]

I have a pptp server running in linux set up on my office LAN. 
 
  Red Hat 6.2
  Kernel rpm RedHat 2.2.19-6.2.7
  Server pptpd PoPToP v1.0.1
 
I can connect to the server and ping to it fine, but I can't ping any other hosts on the office subnet.  I have ip-forwarding turned on and I have proxyarp set in the ppp/options file.  What can be wrong?
 
-- cut from /etc/pptpd.conf --
localip 192.168.0.120
remoteip 192.168.0.100-119
-- end of cut --
 
--cut from /etc/ppp/options--
name vip
noauth
#require-chap
proxyarp
--end of cut--
 
--cut from /etc/ppp/chap-secrets--
vip * vip    
-- end of cut--

                                  192.168.0.254   192.168.0.16
 ________                              ______        _____
|        |                            |      |      |      |
| client |--------------------------> | pptp |----->| host |
|        |                            | srvr |      |      |
|________|                            |______|      |______|
    H                                   H
    H                                   H
    H                                   H
    H===================================H
192.168.0.100     pptp connection     192.168.0.120

please answer me as soon as possible.Thanks


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