Not able to receive emails on Postfix

MEZIANE Yacine

8/6/24, 12:48 PM

I installed a mail server with Postfix and Dovecot on Debian. I can send emails without worries to Outlook, Yahoo, ...BUT I can't receive emails from outside.

I use my internet box (free) as a router. I redirected flows comes on 993, 143, 25 and 587.

I use NOIP as DNS. I added the records needed for the MX part.

yacine@mezianeyacine:~$ nslookup -type=mx mezianeyacine.sytes.net
Server:         192.168.1.254
Address:        192.168.1.254#53

Non-authoritative answer:
mezianeyacine.sytes.net mail exchanger = 10 mail.mezianeyacine.sytes.net.
mezianeyacine.sytes.net mail exchanger = 20 imap.mezianeyacine.sytes.net.
mezianeyacine.sytes.net mail exchanger = 40 pop.mezianeyacine.sytes.net.
mezianeyacine.sytes.net mail exchanger = 1 smtp.mezianeyacine.sytes.net.

Authoritative answers can be found from:

yacine@mezianeyacine:~$

I have verified that my server is listening on the port 25 & 587. Also i have managed the firewall to accept incoming and outgoing connection for port 25

I have found a potential solution here: the issue may that the mail.mezianeyacine.sytes.net don't have any address records:

yacine@mezianeyacine:/etc/apache2/sites-available$ host mezianeyacine.sytes.net
mezianeyacine.sytes.net has address 82.66.16.108
mezianeyacine.sytes.net mail is handled by 20 imap.mezianeyacine.sytes.net.
mezianeyacine.sytes.net mail is handled by 40 pop.mezianeyacine.sytes.net.
mezianeyacine.sytes.net mail is handled by 1 smtp.mezianeyacine.sytes.net.
mezianeyacine.sytes.net mail is handled by 10 mail.mezianeyacine.sytes.net.

yacine@mezianeyacine:/etc/apache2/sites-available$ host mail.mezianeyacine.sytes.net.
Host mail.mezianeyacine.sytes.net. not found: 3(NXDOMAIN)

yacine@mezianeyacine:/etc/apache2/sites-available$ host smtp.mezianeyacine.sytes.net.
Host smtp.mezianeyacine.sytes.net. not found: 3(NXDOMAIN)
yacine@mezianeyacine:/etc/apache2/sites-available$

Could you help me to solve this please ? I'm not sure to what I can do to solve.

1 + 3

debian

postfix

dovecot

Esa Jokinen

8/6/24, 2:47 PM

It seems you don't understand what `MX` records are for.

MEZIANE Yacine

8/6/24, 3:35 PM

May be you can explain to help to solve the issue ?

tsc_chazz

8/6/24, 4:09 PM

An MX record says that a mail responder is listening on a specific named server. What you seem to be missing is the A record which says where that specific mail server lives. Add A records in DNS that map `smtp.mezianeyacine.sytes.net` and `mail.mezianeyacine.sytes.net` to your server's IP address.

Score:1

Server

Esa Jokinen

8/6/24, 6:09 PM

It would be best to start by learning what a DNS MX record is, which helps to understand how to use them. Your current configuration suggests you would need MX records for IMAP, POP, SMTP and "MAIL", but that's not how it works!

As it seems you are only having one server at mezianeyacine.sytes.net handling the mail and it has SMTP banner configured for the same host name, it might be easiest to forget all the subdomains. Having multiple hostnames pointing to a single server does not increase redundancy at all.

You could simply replace all your MX records with a single record:

mezianeyacine.sytes.net. IN MX 1 mezianeyacine.sytes.net.

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