1 Topic by Kawaii

  • Kawaii
  • Kawaii
  • Member
  • Offline
  • From: Cyberia
  • Registered: 2016-02-15
  • Posts: 24

Topic: Changing the Submission port - any problems?

Hello!

My host has decided to block all outbound connections on port 25, 465 and 587. While sending email from blocked ports is not allowed, your server can still receive email it says. If I change the 587 submission port to 5877 does it cause any problems with receiving mail? If I have changed the port and another mail server tried to send me email on 587 would it not just bounce back? Or do emails sent to your server use a different port entirely? Is it okay to keep ports 25 and 465 completely closed in IPTABLES too or can I expect this to also cause problems? I only want my users using the most secure ports and services for sending mails.

Thanks!

----

Spider Email Archiver: On-Premises, lightweight email archiving software developed by iRedMail team. Supports Amazon S3 compatible storage and custom branding.

Kawaii's Website

2 Reply by ZhangHuangbin

  • ZhangHuangbin
  • ZhangHuangbin
  • iRedMail Developers
  • Offline
  • Registered: 2009-05-06
  • Posts: 30,770

Re: Changing the Submission port - any problems?

Port 25 is required to be open on your server for BOTH incoming and outgoing traffic, because it's used to communicate with other mail servers.

Port 587, 465, 110, 143, 993, 995 are free to change.