I ended up with a similar opendkim.service, though not exactly the same….. I intentionally left out any mention of opendkim.conf or opendkim.service in this guide, as there are plenty of online resources for those. The real trick is to get past the install hurdle…. But yes… next would be to get the service RUNNING, then to configure for your specific mail agent (postfix, sendmail), guidance on requirements for your domain, required DNS records, validation of DKIM, SPF, and DMARC setup, etc… All of which can be quite a large topic… 🙂

———————————————-
[Unit]
Description=Opendkim Service
Documentation=man:opendkim(1)
After=network.target

# Note PIDfile is under /run now, (var/run/ has been deprecated and does not work)
[Service]
Type=simple
ExecStart=/usr/local/sbin/opendkim -x /etc/opendkim.conf
PIDFile=/run/opendkim/opendkim.pid
Restart=on-failure
RestartPreventExitStatus=0 255

[Install]
WantedBy=multi-user.target
———————————————-

Then tell systemV that there is a new one
# systemctl daemon-reload

Then
# systemctl status opendkim
# systemctl start opendkim
# systemctl stop opendkim

all seem to function OK. Now to check that postfix will talk to it.

Cheers, Les.

Onwards and sideways …

Cheers, Les.

That’s very odd….
I ran through the instructions again with a brand new Amazon Linux 2023 and didn’t have any problem at all.

‘yum install sendmail-devel’ installs sendmail-milter and sendmail-milter-devel:

It’s possible your configuration is older and slightly different?

Try:
1. ‘yum update’ to get everything to the latest versions and try again
2. ‘yum repolist all’ to see all repositories. I have TWO enabled: ‘amazonlinux’ and ‘kernel-livepatch’

Try those and let me know what you find out.

My output

yum install sendmail-devel
Last metadata expiration check: 0:04:43 ago on Thu Nov 14 01:18:29 2024.
Dependencies resolved.
========================================================================================================
Package Architecture Version Repository Size
========================================================================================================
Installing:
sendmail-milter-devel x86_64 8.17.1-5.amzn2023.0.4 amazonlinux 109 k
Installing dependencies:
sendmail-milter x86_64 8.17.1-5.amzn2023.0.4 amazonlinux 41 k

Transaction Summary
========================================================================================================
Install 2 Packages

Total download size: 150 k
Installed size: 337 k
Is this ok [y/N]:

sudo bash
yum install openssl-devel libbsd-devel autoconf automake libtool

To get the missing sendmail-devel, this appeared to have worked for me …

wget https://mirror.stream.centos.org/9-stream/CRB/x86_64/os/Packages/sendmail-milter-devel-8.16.1-11.el9.x86_64.rpm
yum localinstall sendmail-milter-devel-8.16.1-11.el9.x86_64.rpm

Then your instructions 2-4 worked fine.

Thanks again,
Cheers, Les.

If I find a way round this I will let you know. Amazon seem to be making it so difficult to build secure mail servers that I am almost inclined to give up on them and use Ubuntu instead.

Thanks for your efforts.
Cheers, Les.