[RFCI-Discuss] refusing mail to abuse@ if not the only recipient

[Tim Jackson]

On 20/11/09 17:36, Matus UHLAR - fantomas wrote:

> Which mailers support this technique and how?

Exim does (via it's configurable access control) and I've been doing it for a 
long time - a simplified version of the logic I use is as follows (this is in 
the ACL which runs for each SMTP RCPT command, so the logic should hopefully 
be reasonably readable and applicable to other environments):

...
# set variable m0 to 1 if a non-abuse@ recipient has been seen
# importantly, the m0 variable persists across all SMTP RCPT commands within
# a single transaction
warn local_parts = !abuse
      # this means "if m0 is not 2"
      condition = ${if !={$acl_m0}{2}}
      set acl_m0 = 1

# set variable m0 to 2 if an abuse@ recipient has been seen
warn local_parts = abuse
      condition = ${if !={$acl_m0}{1}}
      set acl_m0 = 2

# send 4xx if an abuse@ recipient is seen and we have seen a non-abuse one
# in this transaction
defer message = Please try again later
       local_parts = abuse
       condition = ${if ={$acl_m0}{1}}

# send 4xx if an non-abuse@ recipient is seen and we have seen an abuse one
# in this transaction
defer message = Please try again later
       local_parts = !abuse
       condition = ${if ={$acl_m0}{2}}
...

If anyone wants to take this further with Exim, the exim-users list is 
probably a better place than here to get help.

Tim