Reference IP during registration process

[JPnyc]

I'm not sure if this should be in the programming discussions section or not, but here it is anyway. I'm doing some testing during the registration process, before the account is actually created.

I already have some plug-ins written hooked on register_add_member_process. I'm successfully referencing certain fields in this matter now:

$vbulletin->GPC['email'];

and what I want to know is, how do I reference IP address in the same fashion? Would it be something like this? :

$vbulletin->GPC['ipaddress'];

Thanks much for any help.