I think you can create an account on DynDns or No-Ip (the basic service is free), and install the client on a Windows or Linux machine of your LAN. This client will let DynDns/No-Ip know your address every now and then (you choose how frequently). Then, from the outisde, you just need to
to know the IP address of your router.
The solution isn't Perl based, but it's easy and should work smoothly.
Michele.