How do I temporarily suspend mail delivery to a specific domain (non-local) with Postfix?

Question

Using Postfix and custom transports I can manage delivery speeds depending on the recipient's domain. (For example, I send max one message per second to *@hotmail.com)

I also use similar rules to block bad destinations (htmail.com is blocked right away, avoiding many loops in the queue).

However, I'd like to temporarily suspend mail delivery to a destination for 24 or 48 hours (mails to *@gmail.com suspended, everything else delivered). Messages would queue up during this time, and would be delivered only when I want by changing the config.

Does anyone know how to do that ?

Thanks

Answer 1

Put messages in a HOLD state

/etc/postfix/main.cf:

smtpd_recipient_restrictions = 
    ...
    check_recipient_access hash:/etc/postfix/hold

/etc/postfix/hold:

gmail.com        HOLD
blah.com         HOLD

Make sure you run postmap hash:/etc/postfix/hold whenever you update the file.

If you want to release all messages on hold, use:

# postsuper -r ALL

Answer 2

To put on hold for specific domain:

postqueue -p | awk 'BEGIN { RS = "" } { if ($7 == "your@domain.com" ) print $1 }' | tr -d '!*' | postsuper -h -

To release for a specific domain:

postqueue -p | awk 'BEGIN { RS = "" } { if ($7 == "your@domain.com" ) print $1 }' | tr -d '!*' | postsuper -H -

Answer 3

You can do this with a transport map:

gmail.com defer: