Setting up iPVanish VPN on Linksys WRT1900ACS connected to Airport Extreme

[Apple_Robert]

My current setup: AT&T Arris Router (main router for U-Verse and Fiber Internet) in one room and my AirPort Extreme in another room connected via Ethernet. I have a Linksys WRT1900 ACS modem arriving tomorrow, and the goal is to use the Linksys router as my always on VPN (iPVANISH) router, which will be ethernet connected to my Airport Extreme which I plan to keep (as is) running a 2.4 and 5GHz channel, so that myself and others can use it when VPN is not needed.

Questions: Have any IPVanish users flashed this modern for DD-WRT and had any problems? Are there any special steps I need to take connecting the Linksys to the AirPort Extreme (which I believe is currently in "off bridge" mode) so that I can connect devices to either modem at will? I am not a network person and am new to this endeavor. Any help / tips in easy to understand terms would be appreciated.

 

[satcomer]

You have to setup a double NAT situation meaning the second router must have the DHCP setup in it!

 

[Apple_Robert]

You have to setup a double NAT situation meaning the second router must have the DHCP setup in it!

Thanks for the reply.

AT&T modem > VPN Modem > Airport Extreme

For ease of use, does it matter if the Airport is last or in the middle? By your post, that means I need to set the VPN modem to the NAT setting, correct?