[ale] Strange sendmail (and postfix) spam issue: accepting fail "from" myself?

[Phil Turmel]

On 03/29/2016 04:58 PM, Alex Carver wrote:

> As for the rule, no clue how to write it in sendmail's m4 macros, I use
> exim for the MTA.

I too use exim.  I have a rule that requires senders in the hosted
domain to authenticate:

Sample excerpt from exim.conf:

# In the Main config section
domainlist must_auth_senders = example.com

# In the ACL section under acl_check_rcpt after basic checks but
# before SPF and blacklist checks.
  accept  authenticated  = *
  deny    message        = Local originators must authenticate
          sender_domains = +must_auth_senders


HTH,

Phil