Bug#1095479: exim4-config: Accepts mail for system users by default

[Daniel Gröber]

Package: exim4-config
Version: 4.96-15+deb12u6
Severity: normal
X-Debbugs-Cc: dxld at darkboxed.org

Hi Andreas,

exim4-config's accepts mail for system users such as 'daemon' when
local delivery is enabled. I find this unexpected and undesirable:
who's ever going to read these? They just land in /var/mail and aren't
forwarded to root like postmaster et al.

I reproduced this on a fresh bookworm system with
dc_eximconfig_configtype=smarthost, but on my real mailserver I
deliver using dovecot lmtp (a common setup AFAIK), which (temp)rejects
system users due to dovecot's first_valid_uid=1000 default. This
causes (exclusively spam) for system users get stuck in the mailq
which is ugly.

Is this intentional? Do you think it's still useful?

Thanks,
--Daniel