AdamHolmes
asked on
Trouble with VPN over PPTP in regards to Port Forwarding TCP 1723
I am trying to port forward for a VPN over PPTP. I've done this in the past by simply port forwarding TCP 1723; however, in my current situation it doesn't seem to be working.
What I have done:
-Enabled Routing & Remote Access on a Windows 2003 Server
-Tested the VPN connection inside the local network with success
-Port Forwarded TCP 1723 on the router
-Tested other port forwards on the router successfully (port 80, 443, etc)
-Attempted unsuccessfully to access from outside the router. I get to the Verifying Username & Password screen, but never any further. I would assume this shows that I'm having an issue with GRE 47, but I wasn't aware that I had to do anything to enable this protocol; moreover, on the firewall there is no option to enable this.
Any ideas?
What I have done:
-Enabled Routing & Remote Access on a Windows 2003 Server
-Tested the VPN connection inside the local network with success
-Port Forwarded TCP 1723 on the router
-Tested other port forwards on the router successfully (port 80, 443, etc)
-Attempted unsuccessfully to access from outside the router. I get to the Verifying Username & Password screen, but never any further. I would assume this shows that I'm having an issue with GRE 47, but I wasn't aware that I had to do anything to enable this protocol; moreover, on the firewall there is no option to enable this.
Any ideas?
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ASKER
Oh, I forgot to say, when I run pptpsrv on the server side I get an error.
Error 10048 binding Socket:
WSAEADDRINUSE: Address is already in use
Created socket for GRE protocol test
Listening on PROTOCOL 47 for incoming GRE packets...
--------------
So it would seem as though it is still listening for GRE packets right?
Error 10048 binding Socket:
WSAEADDRINUSE: Address is already in use
Created socket for GRE protocol test
Listening on PROTOCOL 47 for incoming GRE packets...
--------------
So it would seem as though it is still listening for GRE packets right?
If it has a service you can forward, that probably looks after GRE. The problem may lie somewhere else.
Any chance there are 2 NAT (Network Address Translation) devices, such as a modem that is a combined modem and router? That can block GRE. If that is the case the modem needs to be put in bridge mode and the ISP connection configured on the router. If the WAN/public side of the router has a private IP the modem is performing NAT.
There are lots of other things that block GRE such as software firewalls, some anti-virus and such but you have tested locally so that would not be the case.
If stuck, double check with your ISP. A few block 1723, PPTP or GRE, in one way or another.
It's also possible the client location is blocking it. Out going is usually allowed/enabled, but not always.
Just to verify, when you say "tested from outside the router", you were off site, not on-site trying to connect to the external interface? Cannot connect to external IP from LAN side.
Not to desert you, but I won't be around for the next 8 hours. I will check back then.
Any chance there are 2 NAT (Network Address Translation) devices, such as a modem that is a combined modem and router? That can block GRE. If that is the case the modem needs to be put in bridge mode and the ISP connection configured on the router. If the WAN/public side of the router has a private IP the modem is performing NAT.
There are lots of other things that block GRE such as software firewalls, some anti-virus and such but you have tested locally so that would not be the case.
If stuck, double check with your ISP. A few block 1723, PPTP or GRE, in one way or another.
It's also possible the client location is blocking it. Out going is usually allowed/enabled, but not always.
Just to verify, when you say "tested from outside the router", you were off site, not on-site trying to connect to the external interface? Cannot connect to external IP from LAN side.
Not to desert you, but I won't be around for the next 8 hours. I will check back then.
>>"So it would seem as though it is still listening for GRE packets right?"
Sounds like it to me.
Sounds like it to me.
ASKER
Yes, tested outside the router was offsite. The symantec has a public IP so unless there is some weird config in the modem, it should be working bridged. He does have dual WAN connections to it so I'm going to have him unplug the second and retest just incase it is trying to come back out on a different line than I'm coming in on.
If that doesn't work I will contact the ISP and see was the deal is with the GRE. Thanks for the help!
If that doesn't work I will contact the ISP and see was the deal is with the GRE. Thanks for the help!
Let us know how it goes.
--Rob
--Rob
ASKER
Disabling the second WAN didn't help at all.
I have to have the client call their ISP. I will update you when I know more.
THanks for all the help.
I have to have the client call their ISP. I will update you when I know more.
THanks for all the help.
Thanks for the update, keep us posted.
--Rob
--Rob
ASKER
THe problem is with the service provider. They are somehow blocking PPTP connections. He used a different provider with the same settings on the firewall and everything worked perfectly.
Glad to hear you were able to resolve. Must have been frustrating though.
Thanks AdamHolmes.
Cheers !
--Rob
ps- for future reference, which ISP was blocking PPTP? I know a few do.
Thanks AdamHolmes.
Cheers !
--Rob
ps- for future reference, which ISP was blocking PPTP? I know a few do.
ASKER
Comcast cable modem service. It got through via bellsouth DSL.
Good to know.
Comcast is the one big one, I have heard of before. The others seem to be small local/private companies.
Thanks very much.
--Rob
Comcast is the one big one, I have heard of before. The others seem to be small local/private companies.
Thanks very much.
--Rob
ASKER
No problem.
ASKER
I can't seem to find any PPTP passthrough options. I have fuond some IPSec passthrough options, but I know that doesn't help.
Any ideas?