Mail Relay Filtering

Mail Relay options can be accessed from the Options > Mail Relay menu.

The Mail Relay feature filters email passing through CMail Server and stops unauthorised email from passing through the system preventing 'Spam' mail being sent from your network.

Enabling Filtering

  1. Open the Mail Relay Filtering Menu.
  2. Check the Enable Mail Relay Filtering checkbox.

When filtering is enabled, you will need to specify either a single or range of addresses which will be permitted to send mail through CMail Server.

Adding a single address

  1. Click the Add button.
  2. Check the Single Address radio button.
  3. Enter the IP address of the workstation which will be allowed to send mail through the server, e.g. 192.168.0.1 in the Start field.
  4. Click the Save button.
  5. The address you have entered will appear in the IP address range permitted to relay list.

Adding Multiple Addresses

  1. Click the Add button.
  2. Check the Range radio button.
  3. Enter the starting IP address of the range in the Start field, e.g. 192.168.0.1.
  4. Enter the IP address of the end of the range in the End field, e.g. 192.168.0.255.
  5. Click the Save button.
  6. The addresses you have entered will appear in the IP address range permitted to relay list.

Tip: If you are unsure which addresses to add, click the Search button which will enter the address range matching your CMail Server's IP address.

Editing an existing address/address range

  1. Highlight the IP Address/Address Range you wish to edit.
  2. Click the Edit button.
  3. Press the Save button once you have completed your changes.

Deleting an existing address/address range

  1. Highlight the IP Address/Address Range you wish to delete.
  2. Click the Delete button to remove the entry.

Key Phrases passed to Relay
From version 2.4, CMail Server incorporates a new method of relay filtering by using a 'key' method instead of checking the IP address of the remote mail server. When a remote server wishes to relay mail through the local copy of CMail, the remote server will send its relay key as part of the greetings message. If this key matches the list of allowed relay keys in the local servers database, the mail will be relayed. If no match is found, the relay request is rejected.

Enabling Relay Keys

  1. Open Mail Relay from the Options menu.
  2. Check Send Key Phrase to Remote Server.
  3. Click OK.

Adding a Relay Key
There are two ways to add a key to key list. The first is to click the Generate button which will automatically create a key. Enter a comment and click OK to make the key appear in the list. The second method is to manually create a key. 

  1. Click Add.
  2. Enter the desired key value into the key field.
  3. Enter a comment appropriate to the key in the comment field.
  4. Click OK.
  5. The key you generated will appear in the list.

Deleting a Relay Key

  1. Highlight the key to be removed from the list.
  2. Click Delete.

Inform Administrator of Relay Violations
When this box is checked, CMail will email the Administrator with a Relay Violation message if such a violation occurs.

Notes: The key that appears at the top of the list will be treated as the primary key for the local mail server. This means that if the local server wishes to send mail through a remote CMail Server, it will pass the key stored at the top of the list as identification. The remote server must have the local server's primary key in its Key database to allow the relay request.

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