- Plesk for Windows
- MailEnable is used as a mail server.
A lot of spam messages are sent from non-existent mail addresses without SMTP authentication. The following records can be found in
MailEnableAdmin > Servers > localhost > Services and Connectors > SMTP Logs > Activity
CONFIG_TEXT: SMTP-IN E36CEC6EB84241AB821F483914F8F3D9.MAI 1284 203.0.113.2 plesk.example.com ESMTP MailEnable Service, Version: 9.00-- ready at 11/09/17 19:03:42 0 0
SMTP-IN E36CEC6EB84241AB821F483914F8F3D9.MAI 1284 203.0.113.2 EHLO EHLO example.com 250-plesk.example.com [203.0.113.2], this server offers 4 extensions 134 21
SMTP-IN E36CEC6EB84241AB821F483914F8F3D9.MAI 1284 203.0.113.2 MAIL MAIL FROM:<email@example.com> 250 Requested mail action okay, completed 43 36
SMTP-IN E36CEC6EB84241AB821F483914F8F3D9.MAI 1284 203.0.113.2 RCPT RCPT TO:<firstname.lastname@example.org> 250 Requested mail action okay, completed 43 31
SMTP-IN E36CEC6EB84241AB821F483914F8F3D9.MAI 1284 203.0.113.2 DATA DATA 354 Start mail input; end with <CRLF>.<CRLF> 46 6
Because of that, the server is blocked on the Microsoft public mail services, like outlook.com and hotmail.com, with the following message:
CONFIG_TEXT: Recipient: [SMTP:email@example.com]
Reason: 550 5.7.1 Unfortunately, messages from [203.0.113.2] weren't sent. Please contact your Internet service provider since part of their network is on our block list (AS3150). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [CY1NAM02FT007.eop-nam02.prod.protection.outlook.com]
- Server IP 203.0.113.2 is added to Tools & Settings > Mail Server Settings > Relay options > Use no relay restrictions for the following networks .
The open relay is allowed for the server IP, therefore all messages from it are accepted without any authentication.
Delete the record which contains the server IP from Tools & Settings > Mail Server Settings > Relay options > Use no relay restrictions for the following networks .