IP addresses

[Crouching Panther]

I was wondering if anyone could let me know how IP addresses work over the internet.

I have a forum (e107) where I think members my be abusing the system by creating multiple accounts.

Do IP addresses change every so often or do they remain the same for that location?

If I find a member with the same IP address as say 3 other members would this me they are from the same location?

Would the IP addresses be different or the same over networked PCs?

I'm not sure how other forums control this, It wouldn't be a major problem, it's just that I run competitions on the site and it would be unfair to other members if it's being abused.

Thanks, I hope someone can explain this to me.

 

[gregmcc]

Each device on the internet has a unique IP address - its like a street address.

There are 2 types - dynamic and static. Static address are fixed - they never change. Most servers on the net have static IP's

Dynamic IP's change every so often, once your connection is reset, or your machine is rebooted etc. Most DSL/broadband lines are dynamic - they will keep the ip's for a couple of days at most.

IF you have a network with pc's on and a proxy server, or a nat'd gateway the IP the machines will present themselves with will all be the same. If you have a network at home and you all browse via the DSL router you will all come from the same IP.

You could try using cookies and IP's to stop users entering twice.

 

[Crouching Panther]

Thanks gregmcc!

So members IP addresses will then be change every so often, but is it possible to have more than 1 member using the same IP address coming from different locations when not networked?
Example I just checked and I have 4 members with the same IP address, all 4 members are from Durban but different suburbs.

 

[gregmcc]

its possible you could be seeing the proxy server - if you go via SAIX they have a transparrent proxy.

To be 100% sure do a reserve lookup on the IP - if it comes out to cache.something then its a proxy. You should be able to work out if its a client's IP or a proxy IP from the name. Or PM me the IP and I can check for you.

 

[Crouching Panther]

Thanks, you've been a great help, I will check them out.