The mail server is giving me a TIMEOUT!

[hack3rcon]

Hello,
I have a number of virtual machines through which I can access mail servers outside the internal network, such as Gmail:

$ telnet smtp.gmail.com 25
Trying 64.233.184.108...
Connected to smtp.gmail.com.
Escape character is '^]'.
220 smtp.gmail.com ESMTP 5b1f17b1804b1-438dcc13151sm31122455e9.1 - gsmtp

But when I try to connect to the internal mail server from the internal network, a TIMEOUT error is displayed.
I can connect to the internal mail server from outside the network:

$ telnet mail.mywebsite.com 587
Trying XXX.XXX.XXX.XXX...
Connected to mail.mywebsite.com.
Escape character is '^]'.
220 XXX.XXX.XXX.XXX ESMTP Exim 4.97.1 Fri, 31 Jan 2025 06:21:58 -0500

I just can't connect to it from the internal network.

How do I troubleshoot?

Thank you.

 

[hack3rcon]

Hello,
Any idea?

Thank you.

 

[Ohm J]

maybe firewall issued.

O

Post in thread 'Help with setting up smtp for multiple client domains'

Sep 6, 2024

becarefully, "SMTP_BLOCK" might rewrite back to "1" when updating directadmin,
so you must go change setting in custombuild UI from "csf=yes" to "csf=no", this will stop directadmin from rewrite config.



###note, SMTP_BLOCK option just block user from using external smtp service.

• Ohm J

 

[hack3rcon]

maybe firewall issued.

O

Post in thread 'Help with setting up smtp for multiple client domains'

Sep 6, 2024

becarefully, "SMTP_BLOCK" might rewrite back to "1" when updating directadmin,
so you must go change setting in custombuild UI from "csf=yes" to "csf=no", this will stop directadmin from rewrite config.



###note, SMTP_BLOCK option just block user from using external smtp service.

• Ohm J

Hello,
Thank you so much for your reply.
If I disable the firewall and the problem is solved, then how can I have the firewall enabled and this problem solved?

 

[Ohm J]

It's still enabled, it's just stop the directadmin from change back the "SMTP_BLOCK" to "1" again.

 

[Hostmavi]

if you enable in firewall csf setting SMTP_BLOCK = "1"

you should allow the user(s) to make the connection

just add the username from directadmin_account_username
in csf.conf setting

in the file /etc/csf/csf.conf

SMTP_ALLOWUSER = "username"

if you want to allow more users just add more user like this

SMTP_ALLOWUSER = "username,username2,username3"

restart csf whit command

csf -r