How can I send a mail from my outlook or other mail accounts to UNIX server?

Hi all,
I want to send a mail for my business needs from outlook account to an unix server (HP-UX) but I don't send any mail. While I can send from the unix server to my outlook account, I can't send from outlook to unix.

How can I achieve this ? How can I send a mail from my outlook or other mail accounts to unix server? Please help me about this subject.

Thank you very much,
Sincerely,

Exactly this topic has been asked/posted/treated just three weeks ago. Well, it was about sending to a linux server, but... Why don't you use the search function of these forums?

Are you wanting to connect to the HP-UX server with Outlook? Using Pop3 or Imap?

Or are you wanting your Microsoft Exchange server to deliver SMTP mail from Exchange to the HP-UX server?

Two very different activities.

FWIW We're running HP-UX 11.31 and using Sendmail for SMTP, and Cyrus for IMAP. We're using Thunderbird on the clients.