EDIT: Postfix and OpenDKIM are easier than I expected. After 02:30 hours I did have a working Postfix and OpenDKIM config. Hello, I would like to setup a mail relay which signs emails. Would Postfix + OpenDKIM be a good option? I would like to use the mail relay internally between a server which sends invoices and an outbound spamfilter (MX-Relay.com). The latter supports DKIM by only forwarding DKIM signed e-mails. I don't have much experience with configuring Postfix... I would like to know what's a good way to configure a small VM which does only sign and forward emails to the outbound spam filter (also a relay) for delivery? Any suggestions on how to achieve this? Thanks.
