It's a poor way to do security, but it might work OK in a very limited area.
User name/Password authentication is usually better.
You are assuming you are limited to users who are given static IP addresses. Works OK in a small, isolated network. But what happens if more and more people want to use your site? It's the coolest thing since sliced bread, so I want to access it from home too, using my VPN account?
You're also assuming that users can't change their IP address. Only works if you are absolutely sure that every users machine is locked down enough that they don't have permission to change their static IP. Otherwise, I just figure out what the bosses IP address is, go in and change mine, and...voila!
And of course it falls in a heap if you need to connect it to the wild, wild internety.
Bottom line: You could make it work, but it won't scale if you are successful. Plan for success.
User name/Password authentication is usually better.
You are assuming you are limited to users who are given static IP addresses. Works OK in a small, isolated network. But what happens if more and more people want to use your site? It's the coolest thing since sliced bread, so I want to access it from home too, using my VPN account?
You're also assuming that users can't change their IP address. Only works if you are absolutely sure that every users machine is locked down enough that they don't have permission to change their static IP. Otherwise, I just figure out what the bosses IP address is, go in and change mine, and...voila!
And of course it falls in a heap if you need to connect it to the wild, wild internety.
Bottom line: You could make it work, but it won't scale if you are successful. Plan for success.