Two old routers (a 2500 and a 1600) , back to back with a serial cable (Dte Dce, & clocking all properly set)  with two Dlink VPN routers on either side of the routers and PC’s hung off those,1) RIP did nothing ; should it have with just 2 routers...

About to try a site to site VPN using two D-link DIR 130s; one side will be clean, the other going through a PIX.Two questions; will the PIX create issues , and should I place the D-link inside our outside the PIX ?