Secure your system with SELinux

Introduction to SELinux SELinux is well known as the most sophisticated Linux Mandatory Access Control (MAC) System. If you install any Fedora or Redhat operating System it is enabled by default and running in enforcing mode. So far so good. Its available for many years and its not rocket science to use it. This article is supposed to give you some hints how to make your system even more secure and how to solve some troubles SELinux may have on your system. DAC ….Read More

Install and configure DKIM with Postfix on RHEL7

Introduction DKIM (Domain Keys Identified Mail) is a measure against email spoofing, Phishing and SPAM mails. Its easy to implement as you will learn in this article. DKIM signs emails on the outgoing SMTP server, the receiving SMTP can verify the signature by looking up the mail._domainkey TXT DNS record of the respective domain to check if the email originates from that domain or if it is forged. This howto can be used to implement DKIM on a SMTP server ….Read More

Integrate Dovecot IMAP with (Free)IPA using Kerberos SSO

Dovecot can make use of Kerberos authentication and enjoying Single-Sign-On when checking emails via IMAP. This post shows you how you enable this feature. With IPA its rather simple to do so. First enroll your mail server to the IPA domain with ipa-client-install as described in various previously posted articles. Creating a Kerberos Service Priciple Ensure you have a Kerberos ticket as admin user ipa1:~# kinit admin Password for admin@EXAMPLE.COM: ipa1:~# ipa1:~# ipa service-add imap/mail.example.com ——————————————— Added service “imap/mail.example.com@EXAMPLE.COM” ——————————————— ….Read More