Limit reception of email to GreenNet

If you are having your email forwarded from GreenNet to you via SMTP,  we recommend you restrict the range of servers your local office mail server accepts mail from.   This restriction may be implemented in a firewall or in your mail server, to prevent malicious email servers or spammers connecting directly to your system.

The overall procedure is to allow port 25 connections from GreenNet (mail.gn.apc.org or the address from which your receive most email will suffice, but contact us for the full IP address blocks we use) and block them from elsewhere.

Microsoft Exchange 2003

1. Start the Microsoft Exchange System Manager.
2. In the list of settings, go into the correct administrative group and then "Servers", the name of the receiving server and then "Protocols" and "SMTP"
3. Bring up the properties of the Default SMTP Virtual server
4. Under the "Access" tab click "Connection"
5. Select "Only the list below"
6. Click Add, then "DNS lookup" and enter "mail.gn.apc.org"
7. Click OK

More information at http://support.microsoft.com/kb/823019

Microsoft Exchange 2010

Microsoft Exchange 2007 is similar.

1. Start the Exchange Management Console, under Start, All Programs, Microsoft Exchange, Exchange Management Console
2. Go to server configuration, then Hub Transport then look under Receive Connectors at the bottom of the window
3. Click the properties of the receive connector you are using
4. Go to the Remote Network Settings page (assuming this is a Custom, internal, partner or client receive connector)
5. Remove the default range 0.0.0.0-255.255.255.255
6. Click "Add IP address" and enter "217.72.179.0/25" (a reverse DNS lookup would be preferable)
7. Click OK

More information at http://technet.microsoft.com/en-us/library/aa996395.aspx

Please contact us if these instructions can be improved.

Spam may also be less effectively filtered if you have email forwarded from another source to domains managed by GreenNet. If the spam is being sent to a domain you have some control over, you may want to contact us so we can take over the domain and apply greylisting to it.  Unfortunately, if you are receiving email via an account at a large free email provider, this cannot be done, and while we will apply additional anti-spam filters to it, you may also want to report any spam you do receive to them.