How to Allow Unauthenticated Relay from a Specific Subnet

This article describes how to allow a certain IP subnet to send emails, without authenticating, while leaving authentication enabled to prevent spamming.

Issue cause

Users receive a "Relay Denied" error while sending messages without authentication.

Solution

If you cannot enable authentication for the entire server user base, you need to have a certain IP, IP range or subnet that can be allowed remote delivery without authentication. Based on this criteria, delivery to remote domains will be allowed, without the need for users, from the respective IP range, to enable authentication.

NOTE: Any other user connecting from a different IP address, not covered by this rule, will still have to use authentication.

  1. Log into the "Webadmin" interface as the "admin" user account.
  2. Go to "Security & Filtering".
  3. Select "Acceptance & Routing".
  4. Go to the "Routing Basic Settings" tab.
  5. In the "Allow / Disallow relaying" section, click on the "Add IP / Range" button.
  6. From the dropdown box select:
    • Network / Mask if you wish to allow unauthenticated relay for a certain subnet. For example: Network: 10.0.0.0 ; Mask: 255.255.255.0.
    • IP Range if you wish to allow unauthenticated relay for certain IP ranges. For example: From: 10.0.0.1 ; To: 10.0.0.101.
    • Single IP if you wish to allow unauthenticated relay only for a certain IP. For example: IP: 10.0.0.2.
  7. Depending on the option you selected at point 6, you must enter the Network / Mask,  IP Range, or IP, in the fields, below the dropdown box.
  8. Click on the  "Allow relaying from any IP" checkbox.
  9. Leave the "Require authentication" option unchecked.
  10. Click the "Add IP" button.
With these settings the Axigen Mail Server will allow remote delivery of messages without authentication,  from the IP's  defined in this rule.

NOTE: In case of multiple entries that match a certain IP, the first matching entry (top to bottom) will apply.
OS: LinuxWindowsFreeBSDMACOpenBSDNetBSDSolaris
Distros: WindowsDEB based distros amd64