Re: Can't change my internal and external ip addresses

"Nicky" <hackeras@xxxxxxxxx> wrote in message

?/? Jason Edwards ??????:
> "Nicky" <hackeras@xxxxxxxxx> wrote in message
> news:1137156157.220873.51060@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

> Jason thanks for the answers bu here i have some more to ask on what
> you said:

Try ipconfig /displaydns
Then ipconfig /flushdns
Then ipconfig /displaydns

It's just a temporary store of DNS results so the number of external DNS
requests made by your PC is not excessive.

ipconfig /release releases your lease on the IP address you had.

> But what if i wanted a different one for example or anyhting
> random ie.

Then you have to be able to tell the DHCP server to issue the address you want.
It may or may not be possible to configure the DHCP server in your modem/router
to do this.

> I have only 1 pc and iam experimenting with this things and i have set
> the lease for ever. This emans that in autmatic mdoe i wont be abel to
> get an ip differnet that How can i change that? (except of
> doign that manullay)

You probably can't make DHCP issue a different address each time without manual
intervention because it just doesn't work like that.

> So ipconfig /release clears my current ip address and i have nothing
> and then ipconfig /renew gives me the same ip address with a ne lease.

It does.

> 2 questions.

> a) How does it know what was the previous ip address i had before i
> ipconfig /release it? Does it store it in someplace?


> b) When we ipconfig /release then we say we get new lease.
> Does that mean that we get the same lease we had before but just the
> time starts from the beginning, so if it was for 1 week we ghet a lease
> for a whole 7 days while before doing that maybe we where in in the
> middle of our current lease week?

Usually you will get a new lease of the same IP but the exact behaviour depends
on the DHCP server.
It's not unknown for broadband ISPs to have variable lease times because some
customers want a continuous connection and some want it for only a few minutes
each day. Sometimes the lease time gets longer after the first renewal which
usually occurs half way through the current lease. If the IP changed at renewal
time then a lot of people would be very upset because any connection in progress
at the time would be lost. So DHCP tries not to change the IP when the lease is

> But sicne it can identify my NIC(cause of the hardware address) and the
> PC(cause of the hostname) then it always can identify my specific
> equipment.
> Changind the ip address wouldnt make a difference, would it?!

It may not make a difference to you but changing the IP address at lease renewal
time would upset anyone with a download in progress at that time.

> By DHCP you mean the ISP's DHCP server right in a same manner as we do
> when we set our router's built-in dhcp to assign ip addresses for our
> internal hosts.
> Correct?

Yes. There is a DHCP server at your ISP which issues your router with an IP
Your router has a DHCP server which issues IP addresses to your own PCs.

> And if yes, we get this same ip address for how long?
> Until the ISP's lease value for our ip address expires?

When I last used a dynamic IP myself the IP address changed at random times when
the ISP expanded or changed their network.
This could be at intervals of months or years.

> DHCP will usually try to give you the same IP address as far as possible
> this causes minimum disruption to your connection.

> minimum disruption to your connection? Umm, how you mean please?

Most people like to have the same IP address all the time and may have set up
DNS services which depend on it remaining the same.
Even if you have a static IP your ISP may assign it by DHCP.


> Sorry for my too many questions, but i need to get enlightend :-)


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