add last user IP in view
Because it needs lots of coding and building a new module I only give you the tips and the algorithm, you need to know how to build a module.


build a module and create a variable (called IP) using drupal_get_variable, in this way a variable will be created in the `variable`` table.
for any user who visits your website, replace its IP address with the existing one (drupal_set_variable) in the IP variable (so far it is easy to implement).
you need output this variable in your view, so use the hook_views_prebuild ($view) hook function, get the IP and embed it in the view.