can't connect from LAN to vpn server's external address

[bobk]

I only want to do this to test the vpn connection from inside the LAN, to
make sure that clients will be able to connect to office (through my vpn
server) from home. But maybe it can't be done with this setup.

The VPN server is a SBS 2003 that acts as a gateway from our lan to the
internet. LAN ip addr is 10.10.99.9. The WAN NIC is 192.168.1.138. NAT is
supplied by a router/firewall on that faces the internet. So from home we
vpn into office using external IP like 66.28.14.13 which connects us to the
SMS's vpn. OK, that works fine from home. But why can't I connect to the
vpn using 66.28.14.13 from inside the LAN. I used to be able to when the
vpn server wasn't a our gateway out and didn't use NAT. I know it's a
stupid question, but I needs to know. From inside, I get "Error 737:
Loopback was detected." I suppose it has something to do with going out the
same address that I want to vpn back into. But I really need to understand
this. An explaination or a reference to an artical to read would be
appreciated.
Cheers!

 

[Robert L [MS-MVP]]

it is because the NAT and it doesn't make sense to connect to the outside ip from inside. if for some reason, you want to test the inside VPN, you should use private ip insted of publick ip. For more and other information, go to http://howtonetworking.com.

Don't send e-mail or reply to me except you need consulting services. Posting on MS newsgroup will benefit all readers and you may get more help.

Bob Lin, MS-MVP, MCSE & CNE
How to Setup Windows, Network, Remote Access on http://www.HowToNetworking.com
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
This posting is provided "AS IS" with no warranties.
I recommend Brinkster for web hosting!

I only want to do this to test the vpn connection from inside the LAN, to
make sure that clients will be able to connect to office (through my vpn
server) from home. But maybe it can't be done with this setup.

The VPN server is a SBS 2003 that acts as a gateway from our lan to the
internet. LAN ip addr is 10.10.99.9. The WAN NIC is 192.168.1.138. NAT is
supplied by a router/firewall on that faces the internet. So from home we
vpn into office using external IP like 66.28.14.13 which connects us to the
SMS's vpn. OK, that works fine from home. But why can't I connect to the
vpn using 66.28.14.13 from inside the LAN. I used to be able to when the
vpn server wasn't a our gateway out and didn't use NAT. I know it's a
stupid question, but I needs to know. From inside, I get "Error 737:
Loopback was detected." I suppose it has something to do with going out the
same address that I want to vpn back into. But I really need to understand
this. An explaination or a reference to an artical to read would be
appreciated.
Cheers!