Issue:
Spammers send bulk mail where email and reply to are random, and the route cloud mail servers, hmail, cannot be easily blocked by wildcard to solve.
How can we hardcode sending domains instead.
Steps:
Mailscanner in EFA supports wildcarding without the *.
After clicking the "blocklist" link, for an email enter:
So for an email, it would be the @ part.
@fearmongeringtheftcompany.com.
After clicking the IP blocklist link, remove the IP, and enter:
For a mail server, that isn't hmail, use the dot and the domain, like:
.fearmongeringcompany.com
If this company is also doing fake domains (to the right of the @) in their emails, and routing through hmail, update postfix's configuration to do a reverse DNS check.
(e.g. reject_unknown_sender_domain)
If you are the sending server:
1. Make sure your Domino or postfix mail system is sending the correct domain.
- In HCL Domino, is this the FQDN on the main/summary tab of the server document.
- For Postifix, this is updating the smtpd_banner directive (line) in the /etc/postfix.conf file.
2. In the DNS control panel, ensure the sending server A record has a reverse pointer PTR record.
3. Use a SPF TXT tag in your DNS, as well.
4. Domino in R12 support DKIM, and Postfix has supported for many years, and should be set-up.
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