From 666fd3f38e403281351ac56f4ea911dd5dcc7c8d Mon Sep 17 00:00:00 2001 From: Dennis Baaten Date: Wed, 5 Jun 2019 20:14:04 +0200 Subject: [PATCH] Updated DKIM how to (markdown) --- DKIM-how-to.md | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/DKIM-how-to.md b/DKIM-how-to.md index e70552a..42fc5cf 100644 --- a/DKIM-how-to.md +++ b/DKIM-how-to.md @@ -2,7 +2,23 @@ This how to is created by the Dutch Internet Standards Platform (the organization behind [internet.nl](https://internet.nl)) and is meant to provide practical information and guidance on implementing DKIM. # What is DKIM? -to-do. +DKIM stands for **D**omain**K**eys **I**dentified **M**ail and is described in RFC 6376](https://tools.ietf.org/html/rfc6376) with updates in [RFC 8301](https://tools.ietf.org/html/rfc8301) and {RFC 8463](https://tools.ietf.org/html/rfc8463). It is meant to provide the owner of a domain with the means to claim that a message has actually been send by the domain's e-mail server and should therefore be considered legitimate. It works by signing every individual e-mail message with a specific key (private key), so that the receiving party can use a corresponding key (public key) published in the sending domain's DNS record to validate the e-mail authenticity and to check whether the e-mail has not been tampered with. # Why use DKIM? -to-do. \ No newline at end of file +A common used technique used by spammers is to trick the receiving party into believing an e-mail is legitimate by using a forged sender address. This is also known as e-mail spoofing. DKIM has been designed to detect the use of spoofing. If an incoming e-mail does not have a DKIM signature or when it's DKIM signature does not validate, the receiving e-mail server should consider the e-mail to be SPAM. + +# Tips, tricks and notices for implementation +* parked domain +* minimum key length + +# Outbound e-mail traffic +DNS record +Signin in Postfix + +## Implementing DKIM in Postfix with SpamAssassin +**Specifics for this setup** +* Linux Debian 9.8 (Stretch) +* SpamAssassin version 3.4.2 (running on Perl version 5.28.1) +* Postfix 3.4.5 +* BIND 9.10.3-P4-Debian +* OpenDKIM v2.11.0 \ No newline at end of file