cisco 1841 behind ISP router

[lscholer]

Hello,

can anybody tell me, how to configure the

scenario below on a cisco 1841?

My cisco is standing behind a isp router,

which makes nating.

i would like to create a vpn tunnel from the cisco 1841 to another cisco 1841, which is standing behind an isp router too.

How I must handle with nating from the isp?

Thanks in advance,

Lorenz

[attrgautam]

Hi Where are you doing the natting ? Is it on your router or on the ISP Router ? IS the natting static or dynamic

http://www.cisco.com/en/US/tech/tk583/tk372/technologies_configuration_example09186a00800949ef.shtml

This link may help you in the configuaration

[lscholer]

Thanks for your fast answer.

Nating takes place on isp router, this is the Default

on the router.

All traffic which go out in the Internet,get the dynamic address from the wan interface

[spremkumar]

hi

is ur sites connecting to 2 different isps on these locations ?

if no and connecting with the same isp i see some possiblity in establishing the ip connecitvity between your locations if the SP agress for the same.

That will be on your private block in which you can have the vpn tunnels created.

but if its connecting with 2 different SPs and as u said if the natting happens in the SP Edge/Border router dont think its possible to have a vpn tunnel created between them.

regds

[lscholer]

Hi,

the ISP's are different, but I want no to create a tunnel between the isp routers. Behind the ISP Routers there are two cisco 1841 with two ethernet connectors and i want to create a tunnel between these two ciscos.

Thanks in advance

Lorenz

[spremkumar]

hi

in your previous message you have clearly mentioned that its gonna be a dynamic nat at the SP end ,with this i dont think you will be able to setup the tunnels since the ip address required for the reachability between the routers may vary.

In case of creating vpn tunnels u shuld have atleast static ip at one end and u can have dynamic ip at the other ends.

so i dont think its possible out here with the current setup at ur locations to have the vpn connectivity.

regds

[lscholer]

Hi,

the ip address from the ciscos 1841 will be a static an officially address.

What i need to know is, if the spoke setup a tunnel to the static officiall ip address from the hub, which spoke ip address is relevant for the tunnel construction, the dynamic address from the ISP router (nat) or the static address from the spoke?

Lorenz

[attrgautam]

If it is a dynamic address you are getting, the VPN will have to be to the Static IP at the Hub and your source will have to be the ISP IP only as that is the IP that will be reachable on the SP core.

[lscholer]

Hello,

I also think it is so, but i don't know it exactly.

Thanks for your help.

Lorenz