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Blacklist / Whitelist

Manual Blacklist/Whitelist per customer

Blacklists are means to directly tell OSS to drop emails coming from a certain source. Blacklists are considered first, before any other tests are run.

Whitelists are means to directly tell OSS to deliver emails coming from a certain source to the recipient’s Inbox. Whitelists are checked after virus scanning, which means that even if a whitelisted sender sends an infected message, our customers remain protected. After virus checking, if the sender is whitelisted, no other checks will be performed (so even SPF problems can be worked around by WL-ing a sender which would otherwise cause the message to be dropped by OSS – note that this is by no means the preferred way to fix an SPF issue). To see how the filtering process is simplified in the case of BL-ed / WL-ed senders, please check Figure 2 below.



Add entries to the Black- or Whitelist in Machpanel

Blacklists and Whitelists can be set on the company level. To control which addresses, domains and networks are allowed through our spam filter without spam checks, and which ones get blocked by default, you can add entries in the text boxes on the “White & Black list” tab. 

    1. Log in to Machpanel (
    2. Go to Service Director > Exchange Hosting > Accounts 
    3. Choose the company that you'd like to modify and click on the Manage.



4. On the White & Blacklist tab add the entries into the relevant box(es). The lists need to be comma separated. If the given entry doesn’t fit the criteria of the given field (e.g. in the email box, you give a network), the panel will automatically filter the incorrect entries.


5. Hit Save and Apply

In order to clear all entries, click on "Clear all White & Blacklists"