Preventing Backscatter in IceWarp
Posted by , Last modified by on 08 August 2013 04:46 PM
Backscatter has become increasingly harmful because many servers are now listening and querying backscatter lists before accepting email. With this now being seen and becoming more common place it is up to administrators to do what they can to prevent from being listed as a server who sends backscatter. What is Backscatter you might ask, Backscatter is the sending of an NDR to a sender who did not actually send the message being bounced.
For example, a server receives a message from firstname.lastname@example.org that is addressed to an unknown account. Since the account does not exist on the server it would normally send a bounce back to email@example.com letting them know this. Unfortunately in this case the message was actually spoofed and the real owner of firstname.lastname@example.org never sent this message but still could possibly end up with an NDR that would then thoroughly confuse them.
In order to make sure your server is configured to protect against this please follow the steps below.
1. Open the administration console or webadministration interface
2. Navigate to the [Mail, General, Delivery] tab
3. You will now see the drop down labeled "Bounce Back Messages"
4. Choose "Local Senders Only"
5. Save your changes
This will now tell the server that bounces are only to be sent if the message originated from a local recipient and thus would no longer be open to sending backscatter to an unknowing recipient who had their email addresses spoofed.