If you have a firewall, you may want to whitelist and/or blacklist some IPs depending in the origin. Usually it’s easy to find the owner of an IP address, but how can you find the IP address(es) registered by one specific company ?
Let’s say you want to whitelist Technorati bot.
A simple way is to go to http://bgp.he.net/ and enter the company name (e.g. technorati). It will return the IP list as follows:
Result | Description |
---|---|
AS16936 | Technorati, Inc. |
208.66.66.0/23 | Technorati, Inc. |
208.66.65.0/24 | Technorati, Inc. |
208.66.64.0/24 | Technorati, Inc. |
208.66.64.0/22 | Technorati, Inc. |
I understand the AS entries correspond to the Internet provider, and the IP address ranges can be added to your firewall (I use CloudFlare service) whitelist.

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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