Before the configuration, understand that emails have envelope and header senders.
The following is an example of an envelope sender:
MAIL FROM:<admin@example.com>
250 2.1.0 Ok
RCPT TO:<test@domain.com>
250 2.1.5 Ok
An example of a header sender:
From: admin <admin@example.com>
To: test <test@domain.com>
To block emails with empty sender address:
- Log in to the IMSVA Linux Shell.
- Use “vi” to edit /opt/trend/imss/config/imss.ini using the command:
# vi /opt/trend/imss/config/imss.ini
- Search for “blockEmpty”. When you see the parameter blockEmptyMailFrom, set the value to “yes”:
blockEmptyMailFrom = yes
- Save the file and restart imssd using the following command:
# S99IMSS restart
- On the Web management console, go to Policy > Policy List.
- Click Add > Other to add a new rule.
- Set the senders and recipients as you want (Here senders mean envelop senders.). Click Next.
- On the Select Scanning Conditions page, click Header keyword expressions.
- Select From then click Add to add a keyword expression.
- Add the content as “^(\s)*$” (without the quotation marks).
- Choose an action for these mails. In this scenario, select Quarantine to block the empty header sender.
- Provide a name for this rule.