Is it possible to receive mail with postfix through other port than 25?

Duli · #1 3rd October 2007, 02:57 PM

Hello,

I'm learning how to setup a postfix mail server. But I'm doing it at home.

I'm almost sure my ISP blocks port 25.

So I've followed this instructions to change the listening port to 5000.

I was able to successfully send mail from my postfix server to various addresses like gmail, yahoo etc.

But, when I try to send mail TO my postfix server, I get this message after some days:

(my domain is marzanet.dyndns.org, which is a dynamic IP updated in dyndns)

Quote:

Hi. This is the qmail-send program at yahoo.com.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

<duli@marzanet.dyndns.org>:
Sorry, I wasn't able to establish an SMTP connection. (#4.4.1)
I'm not going to try again; this message has been in the queue too long.

So my question is:

Is it possible to receive mail through other port than 25? How would the mail servers know which port on my server is the right one, if it's not the 25 one?!

Here's information on my domain:

Quote:

Hostname: marzanet.dyndns.org
Wildcard: *.marzanet.dyndns.org
Current Service: Host (IP address)
Current IP: 201.6.83.105
TTL: 1 min.
Has Redirect Settings: no
MX Records: NONE (mailservers will try to deliver e-mail messages directly to marzanet.dyndns.org)

Thanks a lot!
Duli

gesho · #2 3rd October 2007, 05:57 PM

I can't quite figure how other than 25 port would work. when inbound email, remote hosts don't know your port, is there way they would get it?

Duli · #3 3rd October 2007, 07:05 PM

gesho: That´s exactly what I was thinking.... So I guess it wouldn´t work..

mooninite · #4 3rd October 2007, 09:02 PM

I believe there are some port redirecting services, but they cost money.

There is no free way to tell mail servers to send mail to a different port other than 25.

Duli · #5 3rd October 2007, 09:09 PM

mooninite: Thanks a lot for the info! Now I can rest in peace and stop wondering!!!

scottro · #6 4th October 2007, 04:49 AM

Wait a sec, isn't there mailhop, offered by dyndns for free? I don't have time to check now, but poke around the dyndns site, I think it used to be free, at least.

The usual warning--if you violate your ISP's TOS, they might call you bad names.
Regardless of what we all feel about it, many ISP's do specifically prohibit mail and web servers for standard home accounts. (My own ISP is rather nebulous about it--there's no specific prohibition, but they do reserve the right to take action if you're using excessive bandwidth.)

twn250 · #7 4th October 2007, 02:46 PM

I think you should look into MailHop Relay at dyndns.
Relay mail to any of the following ports: 24, 25, 587, 2525, 10025, 52525
Check if your ISP got these ports open.
MailHop Relay will cost you $39.95 per year

Duli · #8 4th October 2007, 04:18 PM

Hello, guys! Thanks a lot for all the info!

Indeed Dyndns offers mailhop relay, but as twn250 said, it will cost money:

Quote:

DynDNS MailHop Relay allows you to run your own mail server while DynDNS filters spam through heuristics and DNS-based blacklists and discards viruses. We hold and store your mail if your primary mail server goes down, and we can also deliver your mail to an alternate port.

...

Relay mail to any of the following ports: 24, 25, 587, 2525, 10025, 52525

...

MailHop Relay $39.95 Mail relaying service for one domain name.

Well, anyway, at my office I´ve got a fixed IP with the 25 port open. I was doing it at home just for learning purposes.

This thread was nice to clarify that it´s not possible to setup a mail server to RECEIVE mail through other port than 25.

Thanks again!
Duli

gesho · #9 5th October 2007, 12:25 AM

my ISP also had 25 closed, it took 2x1hour phone holding to get it unblocked.

and if ATT can do it, everyone can do it.

be prepared to talk to have-no-clue tech support. ask for "2nd level expert" straight.

kitsune84 · #10 25th November 2007, 11:38 PM

I feel like a walking advertisement right now, but if you don't have a problem switching to them, EditDNS.net is my dns server and they allow what they call "E-mail Re-route" and it's free, so if that would help you out, then that's great.

You just put the address of your mail server and the port you want it to go to and they relay it off of their own servers to your mail server.

Good luck!

NibblerUK · #11 25th November 2007, 11:57 PM

If your ISP blocks port 25 then you accept mail on another port eg. 26 as well as 25. This avoids that problem entirely. You can add the port redirection at the firewall level on your own server.

kitsune84 · #12 26th November 2007, 12:31 AM

I think the problem was that software is going to default to port 25 in most cases and if someone is trying to check their mail, it's not going to work unless they tell their software to check on port 26. It's not a large problem, but it's a pretty irritating inconvenience.