You can use 2 separate keys on servers with different selectors and use 2 DNS records as public keys (for security reasons it will be better). Recipient of email will query dns record to identify if signature of the email is right or not. It will generate dns request based on the signature and it does not depend from the hosts (either you have 1 or 1000).
Anvar Kuchkartaev [email protected] Original Message From: Davide Marchi Sent: martes, 10 de octubre de 2017 11:04 a.m. To: [email protected] Subject: OpenDKIM on backup MX Hello friends, On Debian Jessie I would like to enable OpenDKIM on my two Postfix servers. My question is how to behave with the secondary backup server. Enable it as on the first and then I copy the key from first to secondary? And how I will write DNS txt record that must take the two servers information? Many thanks! Davide
