{"id":291,"date":"2025-06-09T17:32:01","date_gmt":"2025-06-10T00:32:01","guid":{"rendered":"https:\/\/www.cmsws.com\/blog\/?p=291"},"modified":"2025-06-09T17:32:03","modified_gmt":"2025-06-10T00:32:03","slug":"add-spf-validation-to-postfix","status":"publish","type":"post","link":"https:\/\/www.cmsws.com\/blog\/add-spf-validation-to-postfix\/","title":{"rendered":"Add SPF validation to Postfix"},"content":{"rendered":"\n

Installing and configuring postfix-policyd-spf-python on CentOS 6.11 While CentOS 6.11 is an older release, you can still install and configure postfix-policyd-spf-python to enhance your Postfix mail server’s SPF checking capabilities.<\/p>\n\n\n\n

Important<\/strong>: Before you begin, ensure you have the EPEL repository enabled on your CentOS 6.11 system, as postfix-policyd-spf-python may be available in this repository.
Steps to install and configure:<\/p>\n\n\n\n

Install required packages:<\/p>\n\n\n\n

sudo yum install pypolicyd-spf<\/code><\/pre>\n\n\n\n
If pypolicyd-spf is not available, you might need to install epel-release first.  If pypolicyd-spf is still not found, you may need to look for python-policyd-spf or explore other options like compiling from source, which might be more complex for an older system like CentOS 6.11.<\/p>\n\n\n\n
Add a user for policyd-spf:<\/p>\n\n\n\n
sudo adduser policyd-spf --user-group --no-create-home -s \/bin\/false<\/code><\/pre>\n\n\n\n
This creates a dedicated user for running the SPF policy daemon.
Configure Postfix master.cf:<\/p>\n\n\n\n
Open the Postfix master process configuration file:<\/p>\n\n\n\n
sudo nano \/etc\/postfix\/master.cf<\/code><\/pre>\n\n\n\n
Add the following lines at the end of the file to configure Postfix to start the SPF policy daemon:<\/p>\n\n\n\n
policyd-spf  unix  -  n  n  -  0  spawnuser=policyd-spf  argv=\/usr\/local\/bin\/policyd-spf<\/code><\/pre>\n\n\n\n
Note: Make sure the path to policyd-spf is correct for your installation.<\/p>\n\n\n\n
Configure Postfix main.cf:<\/p>\n\n\n\n
Open the Postfix main configuration file:<\/p>\n\n\n\n
sudo nano \/etc\/postfix\/main.cf<\/code><\/pre>\n\n\n\n
Add the following lines at the end of the file to enable SPF checking and set the policy agent timeout:<\/p>\n\n\n\n
smtpd_recipient_restrictions =
  ...
  reject_unauth_destination,
  check_policy_service unix:private\/policyd-spf<\/code><\/pre>\n\n\n\n
policyd-spf_time_limit = 3600<\/code><\/pre>\n\n\n\n
Important<\/strong>: Ensure check_policy_service unix:private\/policyd-spf is listed AFTER reject_unauth_destination to prevent your system from becoming an open relay.<\/p>\n\n\n\n
Restart Postfix:<\/p>\n\n\n\n
sudo service postfix restart<\/code><\/pre>\n\n\n\n
Verify and test:<\/p>\n\n\n\n
Check your mail logs (usually \/var\/log\/maillog) to see if policyd-spf is running and processing incoming mail.  Test the policy daemon manually by running policyd-spf with sample input as described in the policyd-spf.conf(5) documentation.  Send test emails from various sources to ensure SPF checks are being performed correctly. <\/p>\n\n\n\n
Additional Notes:<\/p>\n\n\n\n
    \n
  • Configuration file: You can customize policyd-spf’s behavior by modifying the configuration file, typically located at \/etc\/python-policyd-spf\/policyd-spf.conf.<\/li>\n\n\n\n
  • Debugging: Increase the debugLevel in the configuration file to get more detailed logging information.<\/li>\n\n\n\n
  • SPF Records: Ensure you have correctly configured SPF records for your domain in your DNS.<\/li>\n\n\n\n
  • DNS Caching: Using a local caching DNS resolver is recommended for optimal performance.<\/li>\n\n\n\n
  • Alternative versions: If you encounter issues with the Python version on CentOS 6.11, you may need to install a newer Python version or explore alternative SPF policy agents like postfix-policyd-spf-perl. <\/li>\n<\/ul>\n\n\n\n
    By following these steps, you should be able to successfully install and configure postfix-policyd-spf-python on your CentOS 6.11 system and enhance your mail server’s security by utilizing SPF validation<\/p>\n","protected":false},"excerpt":{"rendered":"
    Installing and configuring postfix-policyd-spf-python on CentOS 6.11 While CentOS 6.11 is an older release, you can still install and configure postfix-policyd-spf-python to enhance your Postfix mail server’s SPF checking capabilities. Important: Before you begin, ensure you have the EPEL repository enabled on your CentOS 6.11 system, as postfix-policyd-spf-python may be available in this repository.Steps to install and configure: Install required […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[39,25],"tags":[41],"class_list":["post-291","post","type-post","status-publish","format-standard","hentry","category-email","category-linux","tag-postfix"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t