Score:0

EXIM4: Signing Emails with DKIM

co flag

I really am banging my head against the wall with this one. I have tried for serveral days to get dkim signing to work on outbound emails from a server running on Debian 12, exim4 version 4.96, but to no avail. I don't even get DKIM error messages, just nothing.

Here's what I've done so far:

  1. Created a new public-private rsa pair in /etc/exim4/dkim (let's call them domain-private.pem and domain-public.pem)
  2. Updated /etc/exim4/conf.d/transport/30_exim4-config_remote_smtp to include the following:
remote_smtp:
  driver = smtp
  dkim_canon = relaxed
  dkim_domain = <domain name>
  dkim_private_key = /etc/exim4/dkim/domain-private.pem
  dkim_selector = apollo
  1. Added a TXT record to my DNS provider (I won't add more details here for now as I don't think this is the relevant part).
  2. Run update-exim4.conf and restarted the service.

When I try and send an email using exim however, there is no exim signing, no error, nothing. What am I missing?

Thanks in advance.

us flag
Are you getting DKIM headers added to the emails you send?
joe.mse avatar
co flag
@Jasen No, I'm not at all
Score:0
us flag

The key file /etc/exim4/dkim/domain-private.pem must be readable by the account exim runs external deliveries as Debian-exim

also be sure that you are editing the correct configuration (either split or combined)

joe.mse avatar
co flag
The keys are both owned by `Debian-exim`. I'm pretty sure that exim was preinstalled on the server -- how can I tell if it's set up with split or combined configuration? I would have guessed the former since there are lots of sub-files in the `/etc/exim4/conf.d` folders
us flag
split or combined is a setting (dc_use_split_config) in `/etc/exim4/update-exim4.conf.conf` (managed by debconf) presence of files is not indicative.
joe.mse avatar
co flag
Yes, that was the issue. Thank you @Jasen!!
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