[exim] Disable delivery to system aliases

Hello,

Somehow if I send message to user123@??? - Exim delivers it to a
system account user123 (if such exists) - even if domain.com is defined as local and there is
NO such e-mail account configured.

Could not find an answer to this on exim's web-site.

Getting lots of spam on system accounts. HELP!

Tried to disable/change this:

----------
system_aliases:
driver = redirect
allow_fail
allow_defer
data = ${lookup{$local_part}lsearch{/etc/aliases}}
user = mailnull
group = mail
file_transport = address_file
pipe_transport = address_pipe
----------

Did not work out.

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