Overview SMTP is broken by design. It comes from a time when communication partners trusted each other and the NSA was intercepting facsimiles and phone calls instead of internet traffic. To enhance privacy, in 2002 RFC 3208 was added to the SMTP protocol. Unfortunately STARTTLS is only optional, it is not allowed to only accept encrypted connections. The RFC states: A publicly-referenced SMTP server MUST NOT require the use of the STARTTLS extension in order to deliver mail locally. That ….Read More
Tag: Email
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