Specificity of User IP

[Leemy]

I know it's a hard question to answer, but how specific is a user's IP, given by SMF? I'm not questioning SMF's IP tracking ability, I'm questioning what does that IP mean. Because I have tracked IPs and come across multiple legitimate users. I've used track IP to try to root out duplicate members (not allowed on my forum) and spam posters, but I've needed a combination of matching IP and user data (log-in times or errors within minutes of each other). Am I doing this detective work right?


The ultimate question is: do two users on the IP mean the same computer/household? Or neighborhood? Or what

thanks

[busterone]

It could mean that two or more people in the same household are using a router, or the same two or more have only one computer, but they all have an account on your forum.
It could also mean that one person has multiple accounts.   

I have 3 different instances of multiple accounts from the same household.  Two are husband/wife, one is mother/son.   

[lorth]

there is also a chance that they are just using the same internet service provider.
the smaller the ISP, the smaller their pool of IP addresses, the bigger the chance to end up with an IP someone else had the IP before.

if some users share a lot of IPs in a lot of postings with similar dates / times, chances are they have multiple accounts.

it might help to look into cookiedata too, like if some users share the same cookie - could still be just multiple people on one PC. also, cookies come from the users PC and are not a safe bet, as they are easy seperatable / deletable / spoofable / etc. same goes for flashcookies, while fewer users are aware of them.
also, i dont know of any mods for smf who check these infos.

[YogiBear]

I read up a while ago how IP addresses are also 'contended' meaning up to 20 people can be on the exact same IP address at any one time. A set of algorithms tries to work out who will need what ressources at any one time but they don't always get it right hence the net can appear to slow down.

My own IP range is all over the place as being a domestic user, as against business, my IP is dynamic (variable).

Trying to match ISP's to e-mail is often a waste of time as you can get an e-mail address from a variety of servers.

My own approach would be to look out for linguistic similarities.

In short, the whole exercise is a fright.