On 4/1/2011 11:36 AM, Drizzt wrote:
On 2011-04-01 11:22:04 (-0500), Vernon A. Fort<vf...@provident-solutions.com>
wrote:
I'm trying to find a way to block/reject inbound messages forging our
internal email addresses. Meaning their inbound messages using MY email
address but there not originating from my server.
I cannot seem to find the correct solution. Anyone.
Vernon
With restriction classes you can drop this spoofing.
Key is to first seperate your own server(s) (e.g. by giving them an OK
before this check). Afterwards if the sender-domain matches any of your
domain it must be spoofing (as only external servers reach this check)
and you can just reject it.
No need for a restriction class. Just blacklist your own
domain after permit_mynetworks, permit_sasl_authenticated.
Note: this may reject a small amount of legit mail.
a quick example:
# main.cf
smtpd_recipient_restrictions =
permit_mynetworks
# NOTE: remove the next line if not using SASL
permit_sasl_authenticated
reject_unauth_destination
check_sender_access hash:/etc/postfix/sender_access
... other local checks ...
# sender_access
# replace example.com with your own domain name
example.com REJECT only authorized senders may use this address
remember to execute "postfix reload" after editing main.cf.
remember to execute "postmap sender_access" after editing it.
-- Noel Jones
