On Mon, Jan 20, 2020 at 06:04:47PM -0300, V. M. Tame-Reyes wrote:
I apologize in advance, for the following could be too simple, but I can't figure it out. I configured a vps using centos 8, all is working fine but I'm not able to send email from this server. I tried $ telnet smtp.mailtrap.io 25 but it doesn't work yet $ telnet www.google.ca 80 does work and particularly $ telnet smtp.mailtrap.io 2525 does work too. I temporarily disabled the firewall, and selinux, but no luck. Can anyone provide any pointers?
Are you configuring your VPS running CentOS 8 to run an SMTP server on port 25, or are you trying to make your VPS running CentOS 8 talk to an external SMTP server?
It sounds like you are trying to make your VPS talk to an external SMTP server. By default, the firewall shouldn't prevent outbound connections. However, some VPS providers, as well as residential ISPs, do block outbound traffic to port 25, in an attempt to prevent compromised systems from sending spam. I suggest you look at the documentation for your VPS provider and see if you are permitted to send SMTP mail from the host. You may need to relay mail through an authenticated SMTP relay run by the VPS provider.