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PPTP Connected but no Traffic

Started by jgadmin, May 28, 2010, 01:41:14 AM

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jgadmin

I am able to connect to the PPTP server, but I am not able to pass any traffic (I can send out packets, but none come back).  Is there a problem with the service?

eonesixfour

#1
I'm having the same problem, I think the problem is the IPv6 tunnel server and the pptp server share the same IP, because when the PPTP tunnel comes the IP is added via the default route, what IPs do I route over the PPTP tunnel?

jimb

Quote from: jgadmin on May 28, 2010, 01:41:14 AM
I am able to connect to the PPTP server, but I am not able to pass any traffic (I can send out packets, but none come back).  Is there a problem with the service?
You can't pass IPv4, or IPv6 traffic?  You should be able to ping at least the other side of the tunnel via the PPTP interface.

If you can't, it may be a NAT issue if you're behind a NAT.

jimb

Quote from: eonesixfour on May 28, 2010, 02:30:20 AM
I'm having the same problem, I think the problem is the IPv6 tunnel server and the pptp server share the same IP, because when the PPTP tunnel comes the IP is added via the default route, what IPs do I route over the PPTP tunnel?
I notice that when the PPTP tunnel comes up, it delivers a route for the tunnel server IPv4 which points it through my LAN default router, and not through the PPTP tunnel.  If one tries to set up a a 6in4 tunnel to that server, it won't go through the PPTP tunnel, but through the LAN default router.

However, I don't have the "VPN is tunnel endpoint" option set.  This may be why it's delivering this route.  I presume that if I had that clicked on, it would deliver a route pointing it through the PPTP tunnel.  But I haven't tested this yet.

Anyway, if you want to use the static IPv4 that comes with the PPTP tunnel to access the internet, you must have the "use default gateway on remote network" box checked under the "General" tab  "Advanced TCP/IP Settings" CPL window (this is under XP, not sure where they put this on 7, etc).  Under XP this is on by default, not sure about other windows OS (but I presume it's the same).

claas

Hello, first of all big thanks for the great idea of a PPTP tunnel service!!

I enabled the PPTP tunnel on my linux machine. ppp0 is used to get the internet connection with PPPoE and ppp1 is the tunnel to the Frankfurt POP (216.66.80.30). Pinging the IPv4 PPTP endpoint is just fine ( ping 172.31.255.1 ).

But I can not pass traffic through ppp1.

I need a route to the PPTP tunnel server through ppp0.
And I need a second route to the IPv6 tunnel endpoint, trough the PPTP tunnel (ppp1), but both share the same IP.

Can this be achieved? Or should the PPTP server have a different IPv4 adress?


claas

Quote from: jimb on May 28, 2010, 02:49:11 AM
However, I don't have the "VPN is tunnel endpoint" option set.  This may be why it's delivering this route.  I presume that if I had that clicked on, it would deliver a route pointing it through the PPTP tunnel.  But I haven't tested this yet.

I have checked this box, but the same route appears here, too.

# ip route show
216.66.80.30 dev ppp0  scope link  src 85.176.142.132  # <------ this one seems to be wrong
213.191.84.199 dev ppp0  proto kernel  scope link  src 85.176.142.132
172.31.255.1 dev ppp1  proto kernel  scope link  src 184.104.125.112 <--- works fine
192.168.178.0/24 dev eth0  proto kernel  scope link  src 192.168.178.10
192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.10
default dev ppp0  scope link


I tried to change the route, to point to ppp1, but then the tunnel is dead.

jgadmin

Quote from: jimb on May 28, 2010, 02:39:28 AM
Quote from: jgadmin on May 28, 2010, 01:41:14 AM
I am able to connect to the PPTP server, but I am not able to pass any traffic (I can send out packets, but none come back).  Is there a problem with the service?
You can't pass IPv4, or IPv6 traffic?  You should be able to ping at least the other side of the tunnel via the PPTP interface.

If you can't, it may be a NAT issue if you're behind a NAT.
I cannot ping the other side, and I am trying this on my router (no NAT in the way) and Laptop (behind NAT).  Other PPTP VPNs work on my laptop, when I try them, just not the HE one.

jimb

I just tried a PPTP test to the London server and it didn't work.  But PPTP to the Fremont, CA, USA server works.

eonesixfour

Quote from: jimb on May 28, 2010, 02:39:28 AM
You can't pass IPv4, or IPv6 traffic?  You should be able to ping at least the other side of the tunnel via the PPTP interface.

If you can't, it may be a NAT issue if you're behind a NAT.

I can't ping the other side of the PPTP tunnel (172.31.255.1) but packets are being sent back and forth from my end to the remote end of the PPTP connection just fine or the tunnel would keeping timing out and dropping, which is what happened before I realised what was going on with the PPTP/IPv6 tunnel server sharing the same IP and tried to re-route it over the tunnel, which caused the tunnel to drop.

I'm on the LA server, going to try the Freemont server.

jimb

Quote from: claas on May 28, 2010, 02:56:53 AM
Quote from: jimb on May 28, 2010, 02:49:11 AM
However, I don't have the "VPN is tunnel endpoint" option set.  This may be why it's delivering this route.  I presume that if I had that clicked on, it would deliver a route pointing it through the PPTP tunnel.  But I haven't tested this yet.

I have checked this box, but the same route appears here, too.

# ip route show
216.66.80.30 dev ppp0  scope link  src 85.176.142.132  # <------ this one seems to be wrong
213.191.84.199 dev ppp0  proto kernel  scope link  src 85.176.142.132
172.31.255.1 dev ppp1  proto kernel  scope link  src 184.104.125.112 <--- works fine
192.168.178.0/24 dev eth0  proto kernel  scope link  src 192.168.178.10
192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.10
default dev ppp0  scope link


I tried to change the route, to point to ppp1, but then the tunnel is dead.
OH wow.  I just realized that the PPTP server and 6in4 servers appear to use the same IPv4 address!  I was using the DNS name so didn't realize it mapped to the same IP.  I really shouldn't stay up until 3AM answering posts on here.  :P

Well, that'd do it.  You can't route the 6in4 tunnel through the PPTP tunnel without breaking connectivity to the PPTP tunnel.

Perhaps Windows and OSX has some "magic" which deals with this or something, since I presume it was tested and worked for windows, but maybe linux doesn't?  I wanted to test this by clicking that box on and seeing how it traced, but the london PPTP didn't work for me at all (connected, didn't pass traffic).  Now I'm too tired to play anymore tonight.

Remember, this is beta.  :P

eonesixfour

#10
Does anyone have a working pptp config for linux (or even better for debian) they can paste?

The reason I ask is the pptp tunnel is up and passing packets back and forth, but on the tunnel page it always reports the tunnel is down.

kcochran

Reporting down while it appears up could also be a bug on this side.  :D

The easy test is if you can ping the v4 address of your side of the PPTP connection from somewhere else, then it's up.

jgadmin

Quote from: kcochran on May 28, 2010, 03:56:30 AM
Reporting down while it appears up could also be a bug on this side.  :D

The easy test is if you can ping the v4 address of your side of the PPTP connection from somewhere else, then it's up.

I can ping it even when the PPTP connection is not running.

eonesixfour

Quote from: kcochran on May 28, 2010, 03:56:30 AM
The easy test is if you can ping the v4 address of your side of the PPTP connection from somewhere else, then it's up.

While I can ping the IP, no traffic comes over the PPTP link when I use ngrep to sniff packets.

kcochran

Gah, I meant if you can ping 172.31.255.1, then it's up.  I think it's too early in the morning.