Blocking Spam - The access File

The access file is similar to The spammers File, but offers more options and flexibility. For example, with the access file you can:

• Reject E-Mail (e.g. Spam) from specific users, domains, IP addresses, and networks.

• Specify the text (or use sendmail's default) of messages to return to senders of rejected E-Mail.

• Accept E-Mail from specific users within a domain, while rejecting E-Mail from all other senders in the domain.

• Reject e-mail sent to specific local users.

There are also a number of other features of the access file, which are documented in the ~/usr/local/sendmail/cf/README file.

Installation

The access file functions can be installed by modifying your sendmail configuration file (~/etc/sendmail.cf). You can do this by using the sendmail M4 macros, which include ready-to-use configuration files with the full anti-spam support. Connect to your server via Telnet or SSH and do the following.

1. Install the sendmail Configuration Utilities.

2. Copy your current ~/etc/sendmail.cf file to a backup location by running the following command:

   % cp ~/etc/sendmail.cf ~/etc/sendmail.cf.save

3. Install the new anti-spam sendmail configuration file that is approprate for your server's O/S.

   • FreeBSD

     % cp ~/usr/local/sendmail/cf/cf/default.cf ~/etc/sendmail.cf

   • Solaris

     % cp ~/usr/local/sendmail/cf/cf/default-sun.cf ~/etc/sendmail.cf

   NOTE: The anti-spam rules require an ACL account with mail-abuse.org in order to function. To learn more about getting an ACL account, go to MAPS Fee Structure page.

4. Create a file named local-host-names, if it doesn't exist already, in your ~/etc directory on your server. In this file, list all the domains on the server that are allowed to recieve e-mail locally. The list should be one domain per line. Previously, these domains were listed on the Cw line of the sendmail configuration file.

Usage

Create or upload an ~/etc/access text file with the format described in the documentation in the ~/usr/local/sendmail/cf/README file. Then, issue the vnewaccess command:

% vnewaccess