On Wed, Apr 06, 2022 at 07:33:41PM +0200, Matus UHLAR - fantomas wrote:
> this is not an internal domain not out client, these are three subdomains of
> remote domain/organization (different IPs from different IP range) I have no
> relationship with.
>
> I have created special transport for them:
>
> slowsmtp unix - - y - - smtp
> -o syslog_name=postfix/slow
> -o smtp_connection_cache_time_limit=30
>
> and set transport_maps accoringly:
>
> .example.com slowsmtp:
>
> and settings to avoid any concurrency:
>
> slowsmtp_destination_concurrency_limit=1
> smtp_tls_connection_reuse=yes
> smtp_connection_cache_destinations=a.example.com, b.example.com, c.example.com
No wonder there's congestion, you're sending a stream of mail throw a
straw. Do the three domains in question ultimately have a common set of
MX hosts? Or does each have its own? If the MX hosts are shared,
you'll get better behaviour with:
a.example.com slowsmtp:a.example.com
b.example.com slowsmtp:a.example.com
c.example.com slowsmtp:a.example.com
And perhaps a slightly higher concurrency limit (2 or 3?), or better
behaviour with just 1.
--
Viktor.
