SummaryInternal E-Mails are flagged as inbound and blocked by spam filters
OverviewMailEssentials recognizes internal emails as inbound when it's not installed on the Exchange server (non Edge).
The Anti-Spam module is designed to only listen on and scan Inbound SMTP traffic. When internal emails (sent from and to same domain) are blocked, one of the below is true:
- Email is an auto-generated notification and is sent from a server, network device or third party software
- Email is sent from a Mobile device
- Email is sent from an Email Client other then Outlook that sends internal emails through SMTP rather than MAPI
- Email is relayed through multiple Mail Servers internally, which communicate through SMTP between them.
- The same Email Domain is spread through Mail Servers physically located on different cities/countries (communicating outside the LAN)
WorkaroundThe below can be implemented as a workaround:
- Stop SMTP or Exchange Transport service
- In the MailEssentials Configuration, go to General Settings > Settings > Local Domains
- Remove the domain from the list and click Apply
- Go to the Whitelist, add the desired entries and then click Apply (in this case, *@domain)
- Go back to Local Domains, re-add the domain and then click Apply
- From the configuration, go to Anti-spam filters > Anti-Spoofing and enable it adding the IP address of SMTP server/s and then click Apply
- From the configuration go to "Filter Priority" and make sure that Antispoofing is above the whitelist
- Restart the service stopped in step 1
Note: enabling Anti-Spoofing is important for the risk of being impersonated by spammers since there will be email addresses from the local domains in the whitelist module.