Revolving IPs

Hey, stupid question. Does your average home broadband connection use revolving IPs? I've never really noticed for my own but still, I've wondered. How do the ISPs allocate addresses?

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dynamik

The majority use DHCP. It probably appears the same because the modem/route keeps renewing the lease.

chmorin

dynamik wrote: »

The majority use DHCP. It probably appears the same because the modem/route keeps renewing the lease.

The ISP's I have used, used DHCP and alot of WAN devices have that as the default, at least that I have worked on.

it_consultant

Really depends on the carrier - they all use DHCP but the lease duration varies. I have had the same addy for months now.

Devilsbane

If you want a static address, you will have to pay more. Most use DHCP and like Dynamik said, you just keep renewing the same one, but it isn't guaranteed to you.

A. It is easier on their side to not have to manage a ton of static addresses, and B. it stops you from hosting a web server at your house because they can change your address and then DNS will be pointing your users to the old address.

Luie

And, at least for American ISPs that are also phone companies, the address needs to stay relatively stable just in case we get a 'request' for a law enforcement trace. Pretty rare, at least here in rural America, but still conceivable.

Devilsbane

Luie wrote: »

And, at least for American ISPs that are also phone companies, the address needs to stay relatively stable just in case we get a 'request' for a law enforcement trace. Pretty rare, at least here in rural America, but still conceivable.

That is one of the advantages/disadvantages (depending on which side of the table you are sitting on) of Dial Up. Every time you connect you get a new IP address. I used to use this to be allowed to submit multiple votes when the website would log your IP address. Vote -- Disconnect -- Reconnect -- Vote...

Even if you get a new IP address daily, I am sure that the ISP keeps very detailed logs of every IP they give out. So when the FBI shows up and says we need to know who had ip address 172.134.25.6 at 7:55 PM Central on September 7th, 2010 the phone company can turn the information over.

gorebrush

Same in the UK - usually do not get a static IP unless you ask for it, or go for very specific ADSL service.

Most business class ADSL's are static, but not all.

Ahriakin

I work for a cell phone company, 1x handsets can make calls that last(and have that IP) for a few seconds and we still have methods to provide CALEA functions (data tapping for cell phones in the US). Trust me, thinking DHCP somehow shields you from this is a myth