Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

how to enable GRE pass-through

I have a router cisco 1811 and I need enable GRE (Generic Routing Encapsulation. How I can do that?


Re: how to enable GRE pass-through

New Member

I have the same issue and can

I have the same issue and can find no answer despite this discussion being 8 years old!

Anyway my network is very similar to that already described

VPN Client(Win7)---->Internet===>router cisco1841===>VPN Server(Win 2012R2)----> LAN

My LAN has a private address range and I am using NAT. I am forwarding TCP port 1723 and this works but the tunnel cannot be established through the routers as GRE is not passed through. If I move my VPN client onto my LAN and re-test then the tunnel is established so this demonstrates that the problem is not with the client or server.

Has anyone solved this who can share the config needed?



Re: how to enable GRE pass-through

Do you mean to pass through a firewall or through an existing acl?

Can you describe your environment.



New Member

Re: how to enable GRE pass-through

Hi, I have my router cisco 1811 K9, with Failover and LoadBalancing... and with the NAT rules to pass through the respective ports to have Web and Telnet Access...

now I'm trying connect from an external connection, with the windows xp client VPN conection, to my office (internal LAN) Windows 2003 VPN server....

I'm already NAT the ports 1723 Tcp and 1701 Udp but doesn't work....

VPN Client(Win XP)---->Internet===>router cisco1811===>VPN Server(Win 2003-ISA Server2004)----> LAN

Note: I'm not using the cisco vpn client and cisco vpn server, only Microsoft Windows VPN client and server configuration.

Thanks a lot!

Re: how to enable GRE pass-through


I don't have experience with Windows VPN server.

Can anyone help?



CreatePlease login to create content