how to configure IPSec on a cisco router behind an ADSL router

[chamaraw07]

Hi guys

im new to networking , appriciate if anyone can expliain how i could  configure IPSec on a cisco router behind an ADSL router ,

NATing is done by the ADSL router and i need to configure ipsec on cisco, as i cannot configure the public static ip on the cisco router's wan interface (which is connected to ADSL router) how to get this done? 

thanks 

[Mark Malone]

Hi can you not put the adsl into bridge mode so the public ip is pushed back onto the Cisco interface , and just have the modem as dumb terminal and move the nat to the Cisco router? just an option  

[chamaraw07]

hi Mark

if i configure adsl in bridge then do i have to configure PPPoE on the CISCO router?

Thanks

[Mark Malone]

Hi

yes you will the modem basically becomes transparent all config must be moved off it onto Cisco side.We have a lot of remote sites all with IPsec and this is how we have them setup ,. here may be another option but I know this way works

[chamaraw07]

Hi

I will try that ,  Thanks mark