GRE VPN

[Guest]

Hi,
How can we be sure GRE is working?
We have an ISA2004 server that we want to use as a VPN server and
can not seem to connect. Everything we read pretty much is saying to make
sure we have GRE enabled.

What happens is when we try to connect from an external location via dialup
or a cable connection we get timed out with the 721.

Thanks
Steve

 

[Robert L [MS-MVP]]

if both client and server are windows, you may try pptpclnt and pptpsrv tools. check this page for more details,

VPN Troubleshooting Tools
VPN Troubleshooting Tools. 1. PPTPclnt and PPTPsrv to test GRE and PPTP .... Troubleshooting IPSec Tools ...

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
Hi,
How can we be sure GRE is working?
We have an ISA2004 server that we want to use as a VPN server and
can not seem to connect. Everything we read pretty much is saying to make
sure we have GRE enabled.

What happens is when we try to connect from an external location via dialup
or a cable connection we get timed out with the 721.

Thanks
Steve

 

[ESteveP]

Thanks, I will take a look and update you guys.

Thanks Again,
Steve
if both client and server are windows, you may try pptpclnt and pptpsrv tools. check this page for more details,

VPN Troubleshooting Tools
VPN Troubleshooting Tools. 1. PPTPclnt and PPTPsrv to test GRE and PPTP ... Troubleshooting IPSec Tools ...

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
Hi,
How can we be sure GRE is working?
We have an ISA2004 server that we want to use as a VPN server and
can not seem to connect. Everything we read pretty much is saying to make
sure we have GRE enabled.

What happens is when we try to connect from an external location via dialup
or a cable connection we get timed out with the 721.

Thanks
Steve

 

[ESteveP]

Ok, thank you for these tools, used the pptpsrv and clnt and found that my
remote client is sending GRE packets but the server is not recieving them.
Reversed the roles and made the client the server and vice versa and
everything is good in that scenario.

So it looks like my router, manged by my ISP is not allowing inbound GRE or
the ISP is blocking GRE. ISP tells me that my router is wide open and is
acting only like a bridge scince we had a pix behind it. That is as far as
tech support from them goes, one guy told me he never heard of GRE and
wouldnt know how to check.

I also tried connecting our test server to the inet via dialup and then ran
pptpsvr and the client connected and talked fine.

Again I think it is either the ISP or the router. The router btw is a
netopia 7100-c. Sent ISP mgmt a long letter asking for higher level support
with this.

Will keep everyone posted, if interested. Any feed back is greatly
appreciated.

Thanks Again


Thanks, I will take a look and update you guys.

Thanks Again,
Steve
if both client and server are windows, you may try pptpclnt and pptpsrv
tools. check this page for more details,

VPN Troubleshooting Tools
VPN Troubleshooting Tools. 1. PPTPclnt and PPTPsrv to test GRE and PPTP ...
Troubleshooting IPSec Tools ...

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on
http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on
http://www.HowToNetworking.com
Hi,
How can we be sure GRE is working?
We have an ISA2004 server that we want to use as a VPN server and
can not seem to connect. Everything we read pretty much is saying to make
sure we have GRE enabled.

What happens is when we try to connect from an external location via dialup
or a cable connection we get timed out with the 721.

Thanks
Steve

 

[Bill Grant]

GRE (Generic Routing Encapsulation) is an IP protocol, just like TCP or
UDP. PPTP sets up and maintains the VPN connection. The data crossing the
link is encrypted and then encapsulated with a GRE header. If anything in
the path blocks GRE, no data is transmitted and the connection closes.

 

[ESteveP]

Hey all,
Looks like the manager at my ISP got everything going. He did find the
router firewall blocking traffic and the Netopia firmware out of date.
Robert, Thanks for pointing me to those tools, gave me the ammo I needed to
go back to the ISP. Everyone at ISP support line told me that everything
was open on the router and nothing is being blocked. Funny how the manager
found it. Anyway, in the end as long as it is working all is good.

Now I have to figure why the dialup clients work fine but one with a cable
internet connection wont browse

Again...
Thank you all
Steve

 

[Robert L [MS-MVP]]

Thank you for the update.

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
Hey all,
Looks like the manager at my ISP got everything going. He did find the
router firewall blocking traffic and the Netopia firmware out of date.
Robert, Thanks for pointing me to those tools, gave me the ammo I needed to
go back to the ISP. Everyone at ISP support line told me that everything
was open on the router and nothing is being blocked. Funny how the manager
found it. Anyway, in the end as long as it is working all is good.

Now I have to figure why the dialup clients work fine but one with a cable
internet connection wont browse

Again...
Thank you all
Steve