AppleShare Mail Server: How To Prevent Unauthorized Mail Relaying

To disable SMTP relay for ASIP 6.2 to prevent unsolicited email (sometimes called "spam"), follow these directions.

1. Update to Mac OS 8.6 and ASIP 6.2 (ASIP 6.2 is required for some settings).

2. Open the Mail Admin application.

3. Choose Mail Server Settings from the Server menu.

• Click the "Mail In" tab, and put a checkmark in the "Require Local "From" Addresses to exist in Users & Groups."

                       
4. Choose Advanced Mail Server Settings from the Server menu.

• Click the "Network" tab and select "Always Check DNS."
• Click the "Anti-Spam" tab and put a checkmark in "Check Incoming SMTP Connections."
• Put a mark in the radio button "Use default server for spam rejection" (Real-time Blackhole List). Note - all known spammers and relayers of spam will be prevented from connecting to your server.
• Put a checkmark in "Log connection if SMTP name does not match IP address."
• Put a checkmark in "Reject if name does not match address." Note: This will lock out relayers spoofing your email server DNS name, but it will also lock out email servers with misconfigured DNS settings (which happens very frequently).

                       
5. Choose Show Host List from the Server menu.

• Delete all hosts on external networks except those you have modified manually. Do not delete hosts on your local network.

                       
6. Choose Edit Default Host Profile from the Server menu.

• Click the "Mail From" tab and put a checkmark in "Deliver mail from this host to local addressed only (no SMTP relay)."
• Optionally, put a checkmark in "Log recipient rejections to error log." This allows you to log anyone attempting to relay through you.
• Click the "Mail To" tab, and remove the checkmark (if present) for "Relay all SMTP mail via ...."
• Click the "Network", and select "Use Advanced Settings."

7. Edit postmaster settings.

• Open the Web & File admin.
• Choose Show Users & Groups List from the Users menu.
• Edit the settings for the Mail Administrator (postmaster) user account by double-clicking the user in the list.
• Select Mail Settings from the pop-up menu and choose "None."