Blacklist / Whitelist Guide

Mailborder blacklist and whitelist policies are used to allow or deny email based on specific parameters. When an email triggers a rule in one of these policies, spam checks are bypassed. However, virus checks are still performed. Whitelisting has no effect on checks performed for file extensions, MIME types, Geographical location, or any other checks outside of spam checks. 


Default Policies

 A policy specified as the Default with the default check mark applies globally to all email processing where another policy is not matched. If you are hosting multiple domains and do not want the same rule to apply to all of them, you must create a new policy, add your rules, and then assign that policy to the domain or domains in which you wish the rules to apply. 


Directional Flow

"Flow" is the direction the email is traveling respective to the email itself or the Mailborder server.

FROM will match sender email addresses, sender domains, and sending servers (IP or hostname).

TO will match recipient email addresses, recipient domains, and destination servers (IP or hostname).

FROM OR TO matches email addressees, domains, and servers (IP or hostname) in both directions.



Priority impacts the order in which policies and rules are built. Objects are built starting with the lowest priority. e.g. 10 first, then 20, then 30, etc. 


Matching Logic

Rule matching is compounded. When a rule is matched, the rule checking continues to check for additional matches. Policy priority will determine the final match.


Email Address and Domain Matching

Below are some examples of valid formats. Wildcard matching is supported. Rules can match the sender or recipient portion of the email.

Rule Result  Exact email address match 
* Domain match
*@* Subdomain wildcard match
bounce-* Partial email user match


IP Address Matching

The scanning engine does support CIDR matching.


Hostname Matching

Hostname matches the servers involved in the email flow. The typical directional flow match used would be FROM. 

Rule Result Matches
* Matches all servers in
*.[de|dk] Matches all .de and .dk TLDs


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