DbLink extension of PostgreSQL which is used to connect one database to another database.
I have prepared full demonstration on this. Also provide full script with example.
You must visit this post:

As per my knowledge you have to store ip address into different part of integer column. String operation is always against database performance. Simply, you can divide your full length of ip address into different small four part.

In future if analysis is require then also you can easily perform using different columns. I have already created full detailed explanation into my blog. please visit this url, this is really very interesting...