LinuxQuestions.org - PPTP/VPN routing problem

Any VPN/PPTP experts here?

I'm trying to connect to my work LAN from home using VPN, and while the connection appears to be successful, I can't see anything on the network once I'm connected. Even pinging the VPN server itself gets no response.

I followed the instructions here to set up the pptp client, and this is what I see when connecting:

Code:

# pon acmecorp debug dump logfd 2 nodetach

...

<snip>

...

local  IP address 172.16.30.129

remote IP address W.X.Y.Z

Script /etc/ppp/ip-up started (pid 5685)

Script /etc/ppp/ip-up finished (pid 5685), status = 0x0

where W.X.Y.Z is the public IP address of the VPN server. Unfortunately this sets up a so-called IP loop, which I fix using option 4b in that previous link (i.e. change the point-to-point IP address of the ppp0 interface to the internal address of the VPN server):

Code:

ifconfig ppp0 pointopoint 172.16.31.1

Then my routing table looks like this:

Code:

# route -n

Kernel IP routing table

Destination    Gateway        Genmask        Flags Metric Ref    Use Iface

172.16.31.1    0.0.0.0        255.255.255.255 UH    0      0        0 ppp0

192.168.0.0    0.0.0.0        255.255.255.0  U    0      0        0 ath0

169.254.0.0    0.0.0.0        255.255.0.0    U    1000  0        0 ath0

0.0.0.0        192.168.0.1    0.0.0.0        UG    100    0        0 ath0

Which apparently gives me no route to the 172.16.0.0 network, so I add one:

Code:

# route add -net 172.16.0.0/16 dev ppp0

But still no joy, no successful pings.

Since I am apparently connecting successfully, I assume the problem is just down to routing. But how should the routing be set up? For reference, the routing table on a Windows client that has successfully connected to the VPN server (over the wireless network at work) looks like this:

Code:

Network Destination        Netmask          Gateway      Interface  Metric

          0.0.0.0          0.0.0.0      192.168.1.1  192.168.1.117  25

          W.X.Y.Z  255.255.255.255      192.168.1.1  192.168.1.117  25

        127.0.0.0        255.0.0.0        127.0.0.1      127.0.0.1  1

      172.16.0.0      255.255.0.0    172.16.30.130  172.16.30.130  1

    172.16.30.130  255.255.255.255        127.0.0.1      127.0.0.1  50

  172.16.255.255  255.255.255.255    172.16.30.130  172.16.30.130  50

      192.168.1.0    255.255.255.0    192.168.1.117  192.168.1.117  25

    192.168.1.117  255.255.255.255        127.0.0.1      127.0.0.1  25

    192.168.1.255  255.255.255.255    192.168.1.117  192.168.1.117  25

        224.0.0.0        240.0.0.0    172.16.30.130  172.16.30.130  50

        224.0.0.0        240.0.0.0    192.168.1.117  192.168.1.117  25

  255.255.255.255  255.255.255.255    172.16.30.130              2  1

  255.255.255.255  255.255.255.255    172.16.30.130  172.16.30.130  1

  255.255.255.255  255.255.255.255    192.168.1.117  192.168.1.117  1

Default Gateway:      192.168.1.1

where 172.16.30.130 is the IP address assigned on the VPN. What a mess.

Help!