Denis V (Artprima)

Each time you login to your blog WordPress creates a session cookie which is used to authenticate you. 
By default if someone somehow gets your cookies he (or she) is able to use them to compromise your blog 
(even without having to know your password!). To prevent this you may want to make your auth cookies 
ip-dependent so that they could be valid only for that ip which you used during login.
Use this plugin only if you have a static IP or dynamic which doesn’t change too often. Otherwise, you’ll 
have to enter your login and password each time your IP changes.

IP Dependent Cookies

Plugin IP Dependent Cookies makes your Wordpress installation more secure adding your IP to salt (which makes cookies IP-dependent).

stasionok

With this simple plugin you can restrict extra external requests made with internal WordPress WP_Http class. 
Just put in the filter rules field what you wish to restrict. One url part or url regex per line. 
By default, the plugin returns WP_Error answer for restricted requests. But you can put in response your custom response data.

ROB (rat out blocker)

Restrict execution of certain external requests with partial url or even regex to prevent personal data leakage (as example)

IP Dependent Cookies vs ROB (rat out blocker)