Routing between LAN and PPTP client

[davegr]

Hi all

I have an Asus RT-AC68u running AsusWRT/Merlin 380.68_4. I have a device connected to the PPTP server. The device only supports PPTP, so OpenVPN is not an option.

I can communicate between the router and the PPTP client, however there is no communication between devices on my LAN and the PPTP client. Instead, packets from the LAN destined for the PPTP client IP are routed to the Internet, as shown below (PPTP client IP is 192.168.10.2, Router is 192.168.0.1)

$ traceroute 192.168.10.2
1 rt-ac68u-c520 (192.168.0.1) 1.495 ms 0.853 ms 0.728 ms
2 hostxx-xxx-xxx-x.in-addr.btopenworld.com (xx.xxx.xxx.x) 18.898 ms 18.708 ms 20.028 ms

This happens even though there is a static route as shown below:

admin@RT-AC68U-C520:/tmp/home/root# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.10.2 0.0.0.0 255.255.255.255 UH 0 0 0 ppp10

Clearly the whole point of connecting a client via PPTP is for it to be able to communicate with devices on the LAN, so why isn't that happening here?

I am using the Dual WAN (load-balancing) setup, if this makes any difference.

Many thanks in advance for all advice given.

Dave

 

[eddiez]

A security advice: Switch to OpenVPN through the router. PPTP isn't that secure anymore. Iguess there should a way to enable this for the client (If not: What kind of ancient device are you using as a client?)

 

[davegr]

A security advice: Switch to OpenVPN through the router. PPTP isn't that secure anymore. Iguess there should a way to enable this for the client (If not: What kind of ancient device are you using as a client?)

I knew somebody would say this which is why I made it clear the device does not support anything but PPTP.

The device is a GSM gateway. There is no possibility for anybody except the manufacturer to add OpenVPN support (and I'm not convinced I wouldn't encounter the same routing problem anyway). The device is on a cable network with non routable IP's, so I have no choice but to use a PPTP VPN.

 

[ColinTaylor]

Just tried it here running John's fork (not dual-WAN) and it works fine.

C:\Users\Colin>ping 192.168.10.2

Pinging 192.168.10.2 with 32 bytes of data:
Reply from 192.168.10.2: bytes=32 time=351ms TTL=63
Reply from 192.168.10.2: bytes=32 time=307ms TTL=63
Reply from 192.168.10.2: bytes=32 time=124ms TTL=63
Reply from 192.168.10.2: bytes=32 time=239ms TTL=63

Ping statistics for 192.168.10.2:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 124ms, Maximum = 351ms, Average = 255ms

C:\Users\Colin>tracert 192.168.10.2

Tracing route to 192.168.10.2 over a maximum of 30 hops

  1    <1 ms    <1 ms    <1 ms  router.asus.com [192.168.1.1]
  2   122 ms    68 ms   102 ms  192.168.10.2

Trace complete.

 

[davegr]

Just tried it here running John's fork (not dual-WAN) and it works fine.

C:\Users\Colin>ping 192.168.10.2

Pinging 192.168.10.2 with 32 bytes of data:
Reply from 192.168.10.2: bytes=32 time=351ms TTL=63
Reply from 192.168.10.2: bytes=32 time=307ms TTL=63
Reply from 192.168.10.2: bytes=32 time=124ms TTL=63
Reply from 192.168.10.2: bytes=32 time=239ms TTL=63

Ping statistics for 192.168.10.2:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 124ms, Maximum = 351ms, Average = 255ms

C:\Users\Colin>tracert 192.168.10.2

Tracing route to 192.168.10.2 over a maximum of 30 hops

  1    <1 ms    <1 ms    <1 ms  router.asus.com [192.168.1.1]
  2   122 ms    68 ms   102 ms  192.168.10.2

Trace complete.

Thanks. I'm going to try with dual wan disabled.

I have no idea what John's fork is BTW?

 

[davegr]

Without Dual WAN enabled it works perfectly.

 

[ColinTaylor]

I have no idea what John's fork is BTW?

John's firmware which is forked from an earlier version of Merlin's: https://www.snbforums.com/threads/fork-asuswrt-merlin-374-43-lts-releases-v29e2.18914/

Without Dual WAN enabled it works perfectly.

Yeah, thought that might be the case.