Question my mail does not want to go out and enter

[Remigio]

My ionos VPS is:
Versione Plesk Onyx v17.8.11_build1708180301.19 os_CentOS 7
OS CentOS Linux 7.6.1810 (Core)

here maillog: maillog

I have been reading for 2 days thousands of threads, messages, forums, but I do not come to the head. From my vps I can not send mail, nor to receive it. Now the ionos external mail server is set as mx, but I've also tried:
A mail.100asa.it ipserver
mx mail.100asa.it 10

but none: doesn't work

 

[Monty]

Your server is not able to connect to port 25 of the destination mail servers:
connect to alt1.gmail-smtp-in.l.google.com[108.177.14.27]:25: Connection timed out

=> Check your firewall configuration and make sure you allow outgoing connections to port 25
=> Check with your ISP if they maybe block outgoing connections to port 25
=> You can test it yourself by doing: telnet alt1.gmail-smtp-in.l.google.com 25 (or any other server listed in MX records of a domain)

 

[Remigio]

telnet alt1.gmail-smtp-in.l.google.com 25
Trying 74.125.131.27...

Thank you so much, but as you can see here screenshot-www.yougetsignal.com-2019.02.07-12-29-30 port 25 is already open
Also I can't receive email from gmail (or others)
I see this other issue: Feb 7 12:30:40 100asa postfix/smtp[123190]: connect to gmail-smtp-in.l.google.com[2a00:1450:400c:c0b::1b]:25: No route to host

 

[Monty]

You have 3 different issues, do not mix them up:

1) Outgoing connections (from your server) to port 25 on other mail servers don't work
=> Check your firewall configuration and make sure you allow outgoing connections to port 25
=> Check with your ISP if they maybe block outgoing connections to port 25
=> You can test it yourself by doing: telnet alt1.gmail-smtp-in.l.google.com 25 (or any other server listed in MX records of a domain)

Please perform those 3 steps.

2) "Can't receive email from gmail or others"
=> Port 25 is open on your IP 212.227.193.182, I just checked.
=> However, your domain "100asa.it" currently has 3 MX records in the DNS:

# dig +short 100asa.it MX
10 mx01.1and1.it.
20 mail.100asa.it.
10 mx00.1and1.it.

Only the MX "mail.100asa.it" is pointing to your server. The other 2 MX (lower number = higher priority) point to servers at 1and1.it. So mails to 100asa.it are NOT delivered to your server but going to 1and1.it instead.

Solution: Delete 1and1.it from your MX records. Be aware that your domain 100asa.it is delegated to Cloudflare, so you'll have to check with them how to do that

3) connect to gmail-smtp-in.l.google.com[2a00:1450:400c:c0b::1b]:25: No route to host
=> This is because your server tried to connect to the IPv6 address of the Google server but your server is not configured for IPv6, so it can't reach any IPv6 addresses
=> Not really an issue because your server will try IPv4 when IPv6 connections fail
=> However, you should either properly configure your server for IPv6 or completely disable IPv6. This might help you: How to disable IPv6 addresses on a Plesk server?