Incorrect IP for PPTP client on Rackspace VM

Question

I'm using pptp-linux to connect to a (Windows) VPN. I can connect and authenticate just fine, however I can't ping any hosts on the remote LAN other than the VPN server. I think this is because my VM is assigned the wrong IP address in the wrong subnet. How can I set a static IP address on the correct subnet using pptp-linux?

This seems to be a Rackspace-only issue as I can get a correct IP when connecting from other hosting providers. My ifconfig looks like this:

eth0      Link encap:Ethernet  HWaddr bc:76:4e:08:a6:20
          inet addr:134.213.29.39  Bcast:134.213.29.255  Mask:255.255.255.0
          inet6 addr: 2a00:1a48:7807:103:69d2:7cba:ff08:a620/64 Scope:Global
          inet6 addr: fe80::be76:4eff:fe08:a620/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:29187 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10624 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:40009600 (40.0 MB)  TX bytes:1047755 (1.0 MB)

eth1      Link encap:Ethernet  HWaddr bc:76:4e:08:a9:06
          inet addr:192.168.0.1  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::be76:4eff:fe08:a906/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:27 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:2070 (2.0 KB)

ppp0      Link encap:Point-to-Point Protocol
          inet addr:192.168.0.1  P-t-P:192.168.0.150  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1396  Metric:1
          RX packets:13 errors:0 dropped:0 overruns:0 frame:0
          TX packets:7 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:276 (276.0 B)  TX bytes:70 (70.0 B)

ppp0 is taking the IP address of eth1. The example above uses 192.168.0.1 but eth1 could be anything, and ppp0 will use the same IP.

Once connected to the VPN, I can ping the VPN server host (192.168.0.150), but cannot ping any other hosts on the 192.168.0.0/24 subnet. Why not, and how can I fix this?

score 0 · Answer 1 · edited Jun 11 '20 at 10:02

After a lot of trawling, I came across this post on the DDWRT forums:

If someone have same problem, I figured it out.

Solution is quite simple, in PPTP Config is needed to put "noipdefault", so new value of MPPE Encryption is noipdefault mppe required

My /etc/ppp/peers/name config to connect to a CHAPS-v2 authenticated VPN now looks like this:

pty "pptp 1.2.3.4 --nolaunchpppd"
lock
noauth
nobsdcomp
nodeflate
name lemonymelon
remotename lts
ipparam lts
require-mppe-128
refuse-pap
refuse-eap
refuse-chap
refuse-mschap
noipdefault

Incorrect IP for PPTP client on Rackspace VM

1 Answers1