Getting trolled on a forum and...?

[Raiden94]

I'm on this video game/ movie discussion forum. I've been there for over 2 years. But lately, I started getting trolled by some people. So, on the same laptop, I created another email and then created another forum account under a different name and different info. This was to get back at them without getting into trouble with mods and admins. I started posting using that new account and whatever, and then this new account got a message from one of the admins. He said:
" We don't appreciate duplicate accounts, and they could lead both accounts to being deleted."
That was all he said. Could he have discovered that I created 2accounts? Can admins really do that?

[Agent]

It's extremely easy to work out whether a user has created multiple accounts, as they can check which IP address created and accessed the accounts. An IP address is a special string of numbers and sometimes letters (in the case of IPv6) that uniquely identifies your computer online.

All they have to do (I've done this many times before to check for duplicate accounts) is get the IP address from your first account and see if it's the same as the IP address from the second account. Forum software (the most common being IP.Board and Xenforo) usually have a tool to do this built into the system.