Product manual

GFI MailEssentials 7 Anti-Spam | 123
Option Description
Check if the email header
contains an empty MIME FROM:
field.
Checks if the sender has identified himself in the From: field. If this field is empty,
the message is marked as spam.
Check if the email header
contains a malformed MIME
FROM: field.
Checks if the MIME from field is a correct notation as defined in the RFCs.
Maximum number of recipients
allowed in email
Identifies emails with large amounts of recipients and flags them as SPAM.
Check if the email headers
contain different SMTP TO: and
MIME TO: fields.
Checks whether the SMTP to: and MIME to: fields are the same. The spammers email
server always has to include an SMTP to: address. However, the MIME to: email
address is often not included or is different.
NOTE:
This feature identifies a lot of spam, however some list servers do not include
the MIME to: either. It is therefore recommended to whitelist newsletter
sender address to use this feature.
Verify if sender domain is valid
(performs DNS lookup on MIME
FROM:)
Performs a DNS lookup on the domain in the MIME from field and verifies the domain
validity.
NOTE:
Ensure that the DNS server is properly configured to avoid timeouts and slow
email flow.
Maximum numbers allowed in
the first part of the MIME
FROM: field:
Identifies the presence of numbers in the MIME from field. Spammers often use tools
that automatically create unique reply-to: addresses by using numbers in the
address.
Check if email contains
encoded IP addresses.
Checks the message header and body for URLs which have a hex/octal encoded IP
(http://0072389472/hello.com) or which have a username/password combination (for
example [e-mail]).
The following examples are flagged as spam:
http://12312
www.microsoft.com:hello%01@123123
Check if email contains remote
images only. Minimum HTML
body size
Flag emails that only have remote images and a minimal amount of text as spam.
Assists in identifying ‘image only email’ spam.
Check if email contains GIF
images.
Checks if the email contains one or more embedded GIF images. Embedded GIF
images are often used to circumvent spam filters.
IMPORTANT:
Since some legitimate emails contain embedded GIF images, this option is
prone to false positives.
Check if email contains
attachment spam.
Checks email attachments for properties that are common to attachments sent in
spam email. This helps in keeping up with the latest techniques used by spammers
in using attachments to send spam.
Check if the email subject
contains the first part of the
recipient email address.
Identifies the personalized spam email, where spammers frequently include the
first part of the recipient email address in the subject.
3. From the Language tab, select Block mail that use these languages (character sets) to enable
language detection.