1 Topic by nerdtron09

  • nerdtron09
  • Member
  • Offline
  • Registered: 2013-06-10
  • Posts: 57

Topic: telnet to port 25

==== Required information ====
- iRedMail version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Linux/BSD distribution name and version:
- Related log if you're reporting an issue:
====

Hi zhang, one of my clients were having trouble setting up their email client with starttls configuration so I went ahead and edited the dovecot.conf file with the following

disable_plaintext_auth=no
ssl=yes

The problem I am not sure if my mail server is now an open relay or not? Before I edited dovecot, I wasn't able to telnet port 25 of the server from the public internet. But now, I tried to telnet port 25 and I am able to login (although from two different ISP, one is not able to login, one is not).
How am I sure that our mail server is not an open relay?
Thanks.

----

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

2 Reply by ZhangHuangbin

  • ZhangHuangbin
  • ZhangHuangbin
  • iRedMail Developers
  • Offline
  • Registered: 2009-05-06
  • Posts: 31,091

Re: telnet to port 25

nerdtron09 wrote:

The problem I am not sure if my mail server is now an open relay or not?

Not a open relay. Your modification just makes Dovecot accept insecure POP3/IMAP connections.
Dovecot doesn't listen on port 25 (SMTP), but Postfix does.

You should check whether your client's IP address is blocked by iptables or not. Default settings configured by iRedMail should be just fine.