No, it's not. Changes to the DHCP (routers, DNS, WINS, time servers, etc. etc.) are still passed to a DHCP client when it renews it's IP, even if it always assigns the same IP due to a reservation. If you configure it manually you will not get these configuration changes.
-Russ.
I see.
One last thing. The dhcp client asks the dhcp server for a lease renewal when the lease is about to expire or the other way around?
Ans also you said due to reservation. So whats really my case is having a reserved ip address by a dynamic dchp configuration due to the fact that my ISP has an adequate number of ip addresses one per customer?
Dear "Nicky",
please, *PLEAZE* _do_ _read_ RFC 2131. There is everything in it, you're searching for.
Yours, VB.
Client asks for renwal when lead period is half over.
Quite possibly.
-Russ.
Note also that on dial-up there may be no way to get a unique MAC address from each customer. If no other mechanism (such as an account name or password) is used to recognise you for IP configuration purposes then you will simply get the next available IP address from an available pool each time you connect.
On broadband there is a way to get a MAC address which is unique to each customer. So the DHCP server can remember you even if you are offline for days.
Jason
But up until now i thought that every MAC address(hardware address) was unique. Ther cant be for example 2 NICs' with the same MAC address.
6 bytes it has.first 3 for the manufactor and following 3 for the serial itslef that makes it unique!
Most people with dial-up don't have a NIC, just a dial-up modem, either internal or external to a PC. As far as I know there is no provision for a MAC address in a dial-up modem, or if there is it isn't used.
Jason
There can be two NICs with the same MAC, because MACs today are software configurable.
Yours, VB.
yes i guess you are right, vene hardware addresse changes today!
Also i didnt know that dil-modem didnt have a MAC, i though they did, just like NICs.
So what i understand of all these i this:
This all may look that i have a static ip address but actually i havent because i didnt pay for one.
If i had a static ip addresss that would mean that my ISP would actually reserved an ip address for my personal use only but still through dhcp configuration manner at their end by setting an infinite lease time and not by remotely configured one or pre-attached one to my router when they send it over to me(is this possible btw? :-). They cant just manuallly attach an ip address to my router the way i attach one to my local NIC.
What the isp actually does in my case is that upon my first connection he logs my router's wan interface mac address and then associate it to a dynamic ip address that is available from an ip address pool! That way the ISP can remember what i used last time, so it can give me the same ip address next time i will reconnect in case of me disconnecting/powered down or having network problems so my conenction dropped int he first place.
So, i have a dynamic ip address through dhcp assignment manner and it remains the same, confusign as as being static :-), not because it is static but because the ISP has so many ip addresses that he wont care if its 1:1 (1 specific ip address for 1 specific customer). The only way i would lsoe this address would be due to ISP's pool or network reconfiguration.
Is this correct? I hope it is because iam fighting 3 days now for this :-)
ps: Oh, and the lease time is actually an expiration time :-)
Some ISPs can also attach an IP to your login, so that no matter what MAC you arrive on, you recieve the same IP. You'll probably find that they use this scheme rather than attaching the MAC of the router. Try it -- test somebody else's router and see if you get the same IP you used to.
Getting the same IP all the time from DHCP is not a static IP, because as you mention they can change it if they want to, or they can change the other parameters that are handed down along with the IP. But a "predictable dynamic" IP is what many vendors sell as a static and is for most people's purposes just as useful as a static.
Both the time of lease being granted and the time of expiration are available to the operating system via ipconfig /all
-Russ.
ok, here is another thing i find out recently.
My isp's name is Vivodi and i have an adsl modem/router. My friend's isp name is OTEnet. He has only an adsl modem, not router.
My ip address changes ocne at 4 times. His one changes upon very reconnection.
We both have a contract for Dynamin IP assignment. What happens here? Why mine's doesn't change upon reconnection just like my friend's does?
Not that i dont like it but it just pure curiocity. Sometiems though i do want to change it.
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