what port does mail server listen on?

tart666

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May 18, 2002
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I am setting up a mail server on the new Suse 8.1 system. Postfix seems to be working for sending mail, but I can't figure out which port to forward to be able to receive mail. I am not setting up smtp, or pop3, or imap yet, I just want to receive mail on the actual suse box.

Can anyone tell me which port it is? Thanks
 

N11

Senior member
Mar 5, 2002
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MTA's talk and handshake over 25. I don't understand how you are not setting up smtp but at the same time want to receive mail.

How do you want to receive mail? From a mail client? Or you want mail destined for your server to be accepted by your MTA?

As
 

tart666

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May 18, 2002
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For now I just want the server to receive the mail.

Edit: I want to be able to see the mail when I log into the server via ssh/telnet. I don't want to access it via imap/pop3 yet.

I am not even sure what the service called that is responsible for that. Is that MTP on port 57?
 

N11

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Mar 5, 2002
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Originally posted by: tart666
For now I just want the server to receive the mail.

Edit: I want to be able to see the mail when I log into the server via ssh/telnet. I don't want to access it via imap/pop3 yet.

I am not even sure what the service called that is responsible for that. Is that MTP on port 57?

It is called SMTP over port 25. This is the channel that MTA's use to handshake and communicate with one another.
 

Garion

Platinum Member
Apr 23, 2001
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To expand a bit.. An MTA is a Message Transfer Agent, or a piece of software living on the server that does the work of sending and receiving e-mail. The protocol used by Internet MTA's is SMTP, and it runs on TCP port 25. The term MTA might have thrown you off - It is a generic term, but most commonly used as terminology deep within a mail system like Exchange.

So, if you want to be able to send and receive mail on your local server, open up TCP port 25 on your router, and also make sure your mail server is running properly.

- G
 

tart666

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May 18, 2002
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So, if you want to be able to send and receive mail on your local server, open up TCP port 25 on your router, and also make sure your mail server is running properly.
OK, I used to think SMTP was the protocol for client computers to send mail by connecting to the mail server.

Anyway, I forwarded port 25 and i still don't receive any mail. btw, should I be receiving the mail that I send to dude@168.26.9.48 ? (this is a fake name and a fake IP) And what process should be running to receieve the mail?
 

mboy

Diamond Member
Jul 29, 2001
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How can you send mail to fake name and IP and expect to get it to your mail server?
 

ScottMac

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Mar 19, 2001
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If you are just receiving mail on your home box, and want to access it remotely with a terminal program, then you'd want to use something like "pine" (or any of the multitude of *nix mail clients).

The program would be configured like any other mail client: aim it at the ISPs mail server, tell it to retrieve your mail at some interval, and you're ready to go.

If you are looking to receive mail for a group / domain (that will use a mail client to retrieve it from your home system) then you'd be looking for something like "sendmail." In addition to that, you'd have to have your ISP register your system (in their DNS, mail system, etc) to forward any mail destined for your domain to your home system.

It's not a situation where you can just set up a server and the mail will come. The "Internet" needs to be told who and where you are.

If you use something like pine, then you won't have to open your firewall, because the session/mail requests are originating from inside. If you are trying to set up a server (for a group/domain), then you would need to open a hole through the firewall so the outside systems can forward the mail at whatever random time.

Make sure your parograms and patches area all up-to-date; a mess o' bad stuff is likely to be crawling in. The original viruses started with exploits in the mail system (sendmail) .... and after all these years, I still believe they haven't got it completely locked down.

Good Luck

Scott
 

tart666

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May 18, 2002
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If you are looking to receive mail for a group / domain (that will use a mail client to retrieve it from your home system) then you'd be looking for something like "sendmail." In addition to that, you'd have to have your ISP register your system (in their DNS, mail system, etc) to forward any mail destined for your domain to your home system.
So having a www domain name does not mean the mail addressed to it will be sent to my PC automatically?

Edit: Btw, I am running postfix instead of sendmail. Is postfix responsible for receiving mail as well as sending it?
 

ScottMac

Moderator<br>Networking<br>Elite member
Mar 19, 2001
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No, having a domain name will not automatically have mail routed to your mail server. The People you registered with probably offer "mail forwarding" - which means you give them an email address ( like your personal Yahoo, Earthlink, whoever) and they forward all the mail to that mailbox.

You CAN get it set up, but "someone" has to put the proper records (i.e., MX - mail exchange) into the DNS (such that it is propagated). Again, the People you registerd the domain with may offer that service (usually costs extra, above the cost of registration).

Somewhere in the network / Internet there has to be a reference that says"This address will get you this domain" and within that domain (on a DNS that knows about that domain), "this address is responsable for handling mail."

There are likely to be some free/cheap DNS/Domain administration services available, I'm just not familiar with 'em.

Good Luck

Scott