Link to home
Start Free TrialLog in
Avatar of ChristmasRobyn
ChristmasRobyn

asked on

What happens in most cases regarding dynamic IP addresses?

Okay as I understand it there are two kinds of IP addresses, Static and dynamic. Large companies have static IP addresses and register organisation details on RiPE etc. Every other user home or SME uses a dynamic IP address which refreshes every time you restart your computer.

Now my colleague begs to differ, he says:

"Users on Cable regardless of router or computer restart do not get a new IP address

Users on DSL connecting via a router restarting their computer do not get a new IP address, they only do when the router is restarted."

Which is true?
Avatar of hke72
hke72
Flag of Norway image

Dynamic meens it can change period. But you are alowed to lease out an IP-address for a period of time. Therefore you can get the same IP again and again even with dynamic IP. In my office I have dynamic IP, but it has not changed since I started working here.
 
Dynamic addresses are normally held for for a certain number of days decided by your ISP. When this lease is due to expire your router will request a new address. Their DHCP server will normally say 'well you had this address before you can have it again'. Sometimes the DHCP server will give it a new address.

There will also probably be a time out on your address lease, so although the lease may be 8 days long if you don't use that address in 4 days the DHCP server may reuse it and give you a new one next time you logon.
ASKER CERTIFIED SOLUTION
Avatar of Steven Vona
Steven Vona
Flag of United States of America image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Note also that your router and your computer are completely independent in getting addresses; you can have a static IP address for your router with a dynamic IP for your computer, or vice versa, or both can be of the same type (either one). Getting a static IP from an ISP is typically much more expensive (because it allows you to run as a web node, directly accessible by anyone); for your internal network, it's no big deal. If you go the dynamic route, your router provides the address to your computer, while your ISP provides the address to your computer. Therefore, a dynamic IP address for your computer is subject to change whenever either the computer or the router is restarted; a dynamic IP address that the router gets from the ISP is subject to change when the router is restarted or when the connection to the ISP is lost.