Right so we have set up a mail server for our company that does not use imap nor pop at the moment, it is based on smtp port 25 and I can't figure out how to link it with my mail client as it always asks for imap or pop :/
As forcer obliquely mentioned SMTP is for sending mail. And one of the most popular programs to do that is called "Sendmail." Not that you need to know that, but hey...
Anyway to be able to send and receive email you need both an SMTP server and an incoming mail server that speaks either POP or IMAP. I won't go into Exchange here as it is Microsoft's own take on IMAP.
Often times the sending and receiving servers are the same. At work mine is mail.domain.local. It sounds like you may have plugged in the same server (or IP address) for sending email into the receiving (POP/IMAP) mail location in your mail.app. If it didn't work, you will have to bug your IT folks for the POP/IMAP address too.