Hi Noel,
>> On Oct 30, 2017, at 6:42 PM, Noel Jones <[email protected]> wrote:
>>
>> On 10/30/2017 5:07 PM, J Doe wrote:
>>
>> How do I stop backscatter generated from my server in response to the
>> bounces from Gmail ?
>
> This is a very difficult problem to solve. Your choices are a)
> don't accept spam, or b) don't forward to gmail.
>
> There may be information on the web about disabling bounces in
> postfix. Those "solutions" that discard undeliverable mail are not
> supported and not recommended, and won't be addressed here.
Thank you for your reply.
Two things:
1. For anyone following this thread in the future, I thought I’d note that I’ve
been doing some more reading and it turns out that my supposition in my
previous message that I get blocking of messages to non-existent recipients
with Postfix 2.0 and above is correct, but for a different reason than I
thought.
I was reading more about “Rejecting Unknown Local Recipients with Postfix” [1]
and I realized that this document is referring to e-mail to unknown recipients
in the *local domains*. It goes on to specify that those are domains that
match $mydestination, IP addresses in $inet_interfaces or interfaces listed in
$proxy_interfaces.
Because my server is configured to perform virtual domain hosting, I have the
following:
/etc/postfix/main.cf
mydestination = localhost
...but if a message is sent to a non-existent domain that I *virtually host*
for:
/etc/postfix/main.cf
virtual_alias_domains = example.com
virtual_alias_maps = hash:/etc/postfix/virtual
...it generates a NOQUEUE and terminates the SMTP conversation by default. To
catch mail that is addressed to non-existent recipients, I add the following to
my virtual_alias_maps hash file:
/etc/postfix/virtual
@example.com ADDRESS_TO_SEND_TO
...where ADDRESS_TO_SEND_TO is the e-mail address to catch e-mails addressed to
a non-existent domain.
2. Ok, I understand not wanting to talk about disabling bounce messages
entirely, but I wondered if there was a more “nuanced” approach to that.
Is it possible to have conditional logic on SMTP error codes ? Going through
my logs I noticed that when Gmail detects that a message I forward to a Gmail
recipient is missing DKIM information, it generates an SMTP error code of:
500-5.7.1. Can I then configure bounce messages based on the following:
IF SMTP error code = 5.7.1
AND remote server = GMail
DON’T generate a bounce message (my server)
ELSE
Generate bounce messages (my server)
Thanks,
- J
Sources:
[1] www.postfix.org/LOCAL_RECIPIENT_README.html
