Configure CSF to allow outbound SMTP

email whm
user3583721 picture user3583721 · Oct 12, 2014 · Viewed 13.6k times · Source

I have a web app that sends email via SMTP (Gmail, Zoho Mail servers). The thing is, the email sending works in my localhost but not on my VPS (using WHM).

I contacted support and the guy replied:

If your VPS has ConfigServer Firewall (CSF) installed then this would most likely be causing the problem. As it is working on localhost but not externally this certainly sounds like it might be the case. You will need to review the firewall configuration on the VPS and ensure hose ports are allowed outbound.

But when it comes to server management and configuration, I'm totally lost. I did check the CSF settings page on WHM but not sure where to start.

Any recommendation or solution would be appreciated.

Answer

Ansd picture Ansd · Dec 1, 2014

You have to allow outgoing traffic to ports 25, 465, 587 and in the case of Mandrill 2525 as will. You should actually be fine enabling only the one you will connect to. So:

sudo vim /etc/csf/csf.conf

add 25,2525,465,587 to TCP_OUT, and to TCP6_OUT if you use IPv6.

You might also need to remove that ports from SMTP_PORTS if you have SMTP_BLOCK enabled (if it is set to 1).

Source: https://community.centminmod.com/threads/csf-firewall-info.25/#post-6613

Related questions

How to validate an email address in JavaScript

Is there a regular expression to validate an email address in JavaScript?

Read More
How to validate an email address using a regular expression?

Over the years I have slowly developed a regular expression that validates MOST email addresses correctly, assuming they don't use an IP address as the server part. I use it in several PHP programs, and it works most of the …

Read More
How to send an email using PHP?

I am using PHP on a website and I want to add emailing functionality. I have WAMPSERVER installed. How do I send an email using PHP?

Read More