I've noticed that some traffic coming to my web sites reports a different source IP depending on whether or not the connection is secure. I have two different hostnames, one of which is HTTP, the other, HTTPS, which point to different IPs on the same server. I'm seeing this from users coming from specific networks:
Requests to http://www.example.com come from 22.214.171.124 Requests to https://secure.example.com come from 126.96.36.199
The secure source IP is often just one off from the non-secure source IP, and I'm pretty sure it's the same user making the requests.
What is the benefit of setting up a network like this? I'm assuming it has something to do with security or analytics, but I can't think of a reason why.