Ip Address Question

I have kind of a weird question. When I go to different sites to find my IP (the one assigned by my ISP), I get something like this: 70.144.220.11 (not the actual one, but you get the idea). When I bypass my router and connect right to my modem,in ipconfig I get 70.144.211.15. I know that because it's not a 192.168.x.x address that it can't be something internal to my home net, but shouldn't the two match? I've tried on like 4 different sites, and keep getting the same thing. Am I missing something here? I would say that the sites are just wrong, but I get the same IP from multiple sites.

 

The router assigns an external IP address - one for all your devices.

You can check your IP address here.
http://www.ip-address.org/

 

Yeah but if it was a DHCP addressing would be in the 192.168.x.x range. Also, I doing this with my laptop hooked right into my modem, which doesn't have a router/switch built in. Just cable (coax) in and a single Cat5 out. My router is usually attached after, but I have it disconnected for this.

 

So I can confirm that my IP address is in fact the one the those websites were giving me, so I guess my question is why is ipconfig giving me a different address for ipv4? Would I have an inside and outside IP address?

 

I believe it's simply your ISP issuing you with a new IP when you connect with your modem. That's what my ISP does each time I connect - give me a new IP. Your router isn't involved at all.

 

Yeah the router isn't even connected. Just the modem and a single laptop. But I'm confused with what you mean by my IP is issuing a new IP every time I log in. Even if the IP was changing (which it actually doesn't seem to be...), shouldn't the address given in ipconfig match?

 

Every device will get its own IP. So, no they will not match. DHCP can hand out any address that is setup in it's scope - it doesn't have to be 192.168.x.x, it can be anything (within reason).
The cable modem might have a scope in the 71.x.x.x range, so devices connected to it will get an IP in that range. When you plug in a router, it gets an IP from the cable modem and gives out what ever address are in it's scope (192.168 normally) to devices connected to it. Then the router performs NAT - network address translation to allow you to communicate with the outside world.
To find out how many usable IPs you modem has look at the subnet mask, something like 255.255.255.248 or 252. On your router with the 192 scheme it is likely 255.255.255.0, allowing 254* 'hosts' or devices to connect. (approx. number) also depends on what range is setup in the DHCP to be handed out.
Also when connected directly to the modem the gateway address should match what the websites say your IP is.

 

Ok. I guess where I was getting confused is that I didn't know that a cable modem could use DHCP. So I went and checked the IP again using nothing except the modem and a single laptop, and it has changed (slightly), which demonstrates the DHCP part of it for sure. The subnet is 255.255.252.0, but the default gateway is not the same as the public address.