Incoming emails are being blocked or quarantined by filters even when they are whitelisted. For example, emails are blocked by the Header Checking filter despite it having a lower priority than the IP Whitelist, when the email contains corrupt attachments, or when a domain MIME address is whitelisted, yet it is still quarantined by IPDNS.
GFI MailEssentials processes the emails according to a pre-established order:
- Security and Antivirus modules.
- Anti-spam modules according to their priority list.
A filtering engine that has a higher priority than the whitelist filter may be blocking this email.
Check the following points:
- Whitelisted emails can be blocked if they contain malware since the Email Security engines will always have a higher priority than the anti-spam filters and the whitelist. For example, an email coming from a whitelisted address or domain may still be blocked by GFI if it contains a corrupt archive, detected by the Decompression Engine.
- Ensure that the anti-spam filter scanning order is set so that the Whitelist runs before other filters that are blocking the desired email.
If the filter is higher in priority than the whitelist, it will have already been stopped as identified as spam, and it will never reach the whitelist check.
- There are two types of Whitelist entries, MIME and SMTP. If there is only one of the two entries set-up, add the other as well.
If an email comes from a legitimate source, and it has a malformed header (for instance a mismatch between 'SMTP TO' and 'MIME TO') the email has a high probability of being identified as spam by the Header Checking filter. The solution is to make sure the recipient is added to the Whitelist using both MIME and SMTP options:
- One entry configured to check the MIME recipient
- One entry configured to check the SMTP recipient
Please note that this process refers to the regular Whitelist, and not to the IP Whitelist.
- Ensure that you are on the latest build of GFI MailEssentials.