It changed from 174 (dot something) to 70 (dot something). Why did my home ip address change? Can anyone explain why?
Could it be that you system connects to your ISP via DHCP? If so, then you get a new IPaddress on every connect. I turn my system off every night, and in the morning when I turn it on, it gets a new IPaddress from my ISP via DHCP. -- Tom
Most likely your router lost connection at some point and was given a new IP when it reconnected. It's not unusual for DSL connections.
You are assigned a Dynamic Host Configuration Protocol (DHCP) lease from your ISP at an interval they determine. In order to find out your ISP's available IP's requires simple research. You can trick most routers into changing your IP should you desire it. Thhink of it like this, fixed IP's with millions of customers would become hard to manage for just about any ISP. Automatically renewing IP's are the only real way for them to go unless you request and pay for a fixed IP.
And you only want a fixed IP if you'll be running servers. But that might just be a VPN server for remote LAN access. Even so, you can use a virtual domain, without a fixed IP.