Configure OpenDKIM with Postfix on Debian What are opendkim signing criteria? And how Configure OpenDKIM with Postfix on Debian? Our goal is configure OpenDKIM to sign emails for multiple domains. Linux Debian Security Networking
BIND: Disabling IPv6 responses in bind dns server When using Bind9 as DNS service in your own network, it can be helpful to disable IPv6 (AAAA) responses to avoid the client to try to communicate via IPv6 if it hasn't been setup. Debian Linux Networking
BIND DNS server - permission denied How Fix BIND DNS server permission denied problem after log directory or log file change. Bind server failed with error: isc_stdio_open failed: permission denied Debian Linux Networking
DMARC - Domain-based Message Authentication, Reporting and Conformance What is DMARC DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email authentication method that verifies a message came from a legitimate sender. DMARC is an open standard for email authentication that helps to prevent fraudsters from forging (spoofing) your domain. DMARC checks that the From field matches the domain in DKIM and SPF authentication checks. DMARC also tells email servers how to handle messages that fail these checks and allows recipients to receive reports on emails that fail authentication. Networking Security
Explanation DKIM (DomainKeys Identified Mail) in all details DKIM (DomainKeys Identified Mail) is a system that lets your official mail servers add a signature to headers of outgoing email and identifies your domain’s public key so other mail servers can verify the signature. As with SPF (Sender Policy Framework helps keep your mail from being considered spam. It also lets mail servers detect when your mail has been tampered with in transit. Networking Security
SPF - Sender Policy Framework Email Message Structure To understand how SPF (Sender Policy Framework) and DKIM works is to know the difference between email envelope and email header . Short Definition: Sender Addresses in E-Mails Like paper mail letters, e-mail messages have at least two kinds of sender addresses: one on the envelope and one in the letterhead. The envelope sender address (sometimes also called the return-path) is used during the transport of the message from mail server to mail server, e. Networking Security