Question about IP addresses

On my forum, I have 3 people with the same IP address.
Is it likely to be the same person with 3 accounts, or is it possible for different people to have the same IP address?

 

Different people can have the same IP address, and it is quite common.

When people connect to their ISP with a modem, they get handed an IP Address out of a pool of IPs. They use it while they're online, then when they hangup and are no longer using it, their IP gets put back into the pool. When someone else calls, they get the same IP. So if two people do not know each other, but they use the same Internet provided, then they will show with the same IP address. You'll find when you look at these accounts that they post from a lot of IPs as it changes all the time.

Another example happens for larger ISPs, such as AOL. There are not enough IPs to go around for everyone that connects to their service, so they use a technique called NAT (network address translation). Basically, it makes it so that hundreds of people can go out using the same IP address through the translation. You will typically see multiple IP addresses for the user similar to the example above.

You can do a dns lookup on the ip addresses to get an idea of what is going on with it.

If you have two users posting from the same IP address and that IP address never changes, then the chances are good that they are posting from the same computer.

I hope that helps!

 

Thank you both for those very well written answers.

 

As long as they are not spamming or causing trouble I wouldn't worry to much about it.
It's like Jacqueline and Smyrl said, could be people from the same company (or school), same house,...
So not much to worry about

 

Not its not a spam issue, it's a moral one. You see I know this person, and in one account he has made some very good posts, but on another account he has lead everyone to believe he is someone he is not.

 

If you know him, can't you just ask it then?

"I saw a few accounts with a the same ip as yours. Any chance you registerd a couple of times" or something similar ?

 

Problem resolved!
He didn't have two accounts, because the other person was online same time as him, and one of the IP addresses was a works one.
When they are both at home, both IP addresses are the same though?

 

I'm glad you solved it!

 

I think this guy is a Dr. Jeckel and Mr. Hyde. Although weird, I know people who would do this to either make themselves appear more insightful than others.

My friend has a technical forum and creates dummy posts that ask technical questions then he logs in with his smarty-pants account and answers his own questions. I know that he's trying to populate his forum instead of having someone else do it for money.

As far as your poster, You can not have the same IP at home and at work. You can remote control your home computer but it's not possible to get the same IP at home and at work. His company most likely has a business class internet connection unlike the residential cable/dsl offered for home use. And these are almost always on different backbones that use different addressing schemes.

Compare the posts from each user ID and see if there are similarities in spelling, punctuation, slangs, etc. It's not unheard of for people to create more than one account. After all, some people really believe in the anonymity of the Internet.

My 2 cents.