internet addressing

[carl_townshend]

When I buy ip addresses from my isp, Are they normally different than what the serial (external) ip address of my router interface is that I get from the provider ? and also If I Have one address at home, How to they route to this one address ?

[sean]

It depends. Most ISPs will set up the connection with the customer using a /30. Any other required address space is normally pointed to the customer side of the /30 in a contiguouse block, if possible (probably with a static route statement on the ISP equipment, unless you are running a protocol with them).

[carl_townshend]

Thanks, So If I only have 1 ip address which will be on my serial interface, Could I nat an internal address to this, or would I have to use PAT ? and how do they route this, As its literally only 1 ip, would It just be treated as a directly connected network on there core router ?

[sean]

I would use PAT unless you have a situation that prevents this. Do you know what your subnet mask is? That would be a good indicator of how your ISP is routing you.