Spammers often use tools that automatically create unique reply-to: addresses by using numbers in the address.Ĭheck if email contains encoded IP addresses.Ĭhecks the message header and body for URLs that have a hex/octal encoded IP ( or which have a username/password combination (for example following examples are flagged as spam: Identifies the presence of numbers in the MIME from field. Maximum numbers allowed in the first part of the MIME FROM: field: Note: Ensure that the DNS server is properly configured to avoid timeouts and slow email flow. Performs a DNS lookup on the domain in the MIME from field and verifies the domain validity. Verify if sender domain is valid (performs DNS lookup on MIME FROM:) It is therefore recommended to whitelist newsletter sender address to use this feature. However, some list servers do not include the MIME to: either. Note: This feature identifies a lot of spam. However, the MIME to: email address is often not included or is different. The spammers' email server always has to include an SMTP to: address. Identifies emails with large amounts of recipients and flags them as SPAM.Ĭheck if the email headers contain different SMTP TO: and MIME TO: fields.Ĭhecks whether the SMTP to: and MIME to: fields are the same.

Maximum number of recipients allowed in email If this field is empty, the message is marked as spam.Ĭheck if the email header contains a malformed MIME FROM: field.Ĭhecks if the MIME from field is a correct notation as defined in the RFCs. Enable or disable the various parameters as described below:Ĭheck if the email header contains an empty MIME FROM: field.Ĭhecks if the sender has identified himself in the From: field. The supported Header checking options are available under the General tab.Log on to the MailEssentials Configuration UI as an Administrator and navigate to Anti-Spam > Anti-Spam Filters > Header Checking.Solutionįollow the below steps to configure the Header Checking filter: This article provides the steps necessary to configure various checks supported by this filter that can be enabled to identify spam. The Header Checking Anti-Spam filter can be configured to make several different checks on an email, mostly related to the email’s headers in order to identify spam. It can also be configured to detect particular groups of inconsistencies in MIME/SMTP header values.

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