Mike Hutchinson:
> We have had this exact problem, delivering Retail newsletters to people who
> have opted in for it. A lot of them are on Gmail and Yahoo, and this can be
> difficult with Bulk E-Mail. Despite contact with Google themselves and
> signing up for all of their reporting services regarding Spammy Emails and
> Certified Senders, the best result we've had is to use some Postfix
> configuration to resolve the issue. It does this by gently delivering the
> E-Mails at an acceptable rate (discovered with a LOT of testing and a LOT of
> IP bans (good they're not permanent, huh :). In our environment, on our
> servers, this has resolved the issue, and delivers mail to those domains a
> LOT faster than not performing the config on Postfix. In fact, if we don?t
> configure, we get banned straight away against those domains and cannot
> deliver for several hours afterwards.
>
> We setup the postfix transport file with these entries:
> # destination domains that need to be rate limited
> hotmail.com hotmail:
> msn.com hotmail:
> live.com hotmail:
> windowslive.com hotmail:
> yahoo.com.ar yahoo:
> yahoo.com.au yahoo:
> yahoo.com.br yahoo:
> yahoo.ca yahoo:
> yahoo.com.cn yahoo:
> <snip> - there's more but you get the idea.
>
> Then we setup master.cf:
>
> yahoo unix - - - - - smtp
> hotmail unix - - - - - smtp
>
> Then setup main.cf:
>
> # Slow these destinations to avoid blacklisting, see /etc/postfix/transport
> for domains configured
> hotmail_destination_concurrency_limit = 2
> hotmail_destination_rate_delay = 2s
> hotmail_destination_recipient_limit = 5
> yahoo_destination_concurrency_limit = 4
> yahoo_destination_rate_delay = 1s
> yahoo_destination_recipient_limit = 5
>
> These settings can be tweaked depending on what server you're talking to.
> However, these values work for us, after having dealt with not getting
> 10,000 mails out per week.
>
> I hope this helps.
Interesting. Really.
FYI This should be documented better: Postfix's _rate_delay feature
forces a per-destination delivery concurrency of 1, so you could
drop the _destination_concurrency_limit settings. The Postfix
implementation is utterly simple: schedule one delivery, then
suspend delivery for N second, then schedule the next delivery.
Wietse
