PPTP VPN can connect, but cannot ping

terrio · 02-07-2008, 09:36 AM

Hey Guys,

I have been working trying to setup VPN access from my Slack box to a Windows VPN. I have setup PPTP and am able to connect to the VPN but am unable to ping a machine on the other side of the tunnel.

Here is the output of tail /var/log/messages after I call the VPN. It appears I am connected.

Code:

Feb  7 10:32:10 AXE pppd[32321]: CHAP authentication succeeded
Feb  7 10:32:10 AXE pppd[32321]: MPPE 128-bit stateless compression enabled
Feb  7 10:32:11 AXE pppd[32321]: local  IP address 10.22.37.51
Feb  7 10:32:11 AXE pppd[32321]: remote IP address 10.22.127.1

However, now when I try to ping a machine within the VPN it fails. Any idea what I could be missing?

Thanks

bsdunix · 02-07-2008, 10:31 AM

Quote:

However, now when I try to ping a machine within the VPN it fails. Any idea what I could be missing?

Just a guess, maybe the remote network is setup not to accept ping requests or send ping replies.

thecarpy · 02-07-2008, 11:59 AM

1. ping yourself 10.22.37.51
2. the other side 10.22.127.1
3. ping another system in the target network, if that fails, it is a routing issue - I think ;-)

add this route:

route add -net 10.22.0.0 netmask 255.255.0.0 gw 10.22.127.1

if that does not help, please print your routing table ...

terrio · 02-08-2008, 01:02 PM

Thanks all for the info. BSDUNIX you hit the nail on the head, pings are disabled on the network I am trying to connect.
I so I moved forward with thecarpy's suggestion to add the entry to the route table, and then attempted to connect to my
workstation using VNC, however the connection timed out and failed. I am unable to determine why this could be, so I have
included my routing table below. Does everything look ok?

Code:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.22.127.1     *               255.255.255.255 UH    0      0        0 ppp0
localnet        *               255.255.255.0   U     0      0        0 eth0
10.22.0.0       10.22.127.1     255.255.0.0     UG    0      0        0 ppp0
loopback        *               255.0.0.0       U     0      0        0 lo
default         192.168.1.1     0.0.0.0         UG    1      0        0 eth0

Thanks for the help!

terrio · 02-12-2008, 06:59 AM

Thanks for all the help! I now have VPN and VNC working. It turns out that the issue was related to routing. It turns out that the machine I was trying to remote to was on a different subnet, so I had to change the route to allow for this. Thanks again.