The mailing list for listmasters using Sympa

[Matt Taggart <address@concealed>]

On 7/5/22 14:05, Ruud Baart wrote:
> Hi,
>
> My Sympa installation (6.2.68) works ok with postfix on my Debian server 
> but it is too fast. I get errors like:
>
>     Jul  5 17:47:52 mail postfix/smtp[2888446]: 4D48D81019:
>     to=<address@concealed>, relay=smtp-in.orange.fr[80.12.26.32]:25,
>     delay=3.4, delays=0.13/0.09/3.1/0, dsn=4.0.0, status=deferred (host
>     smtp-in.orange.fr[80.12.26.32] refused to talk to me: 421
>     opmta1mti29nd1 smtp.orange.fr 8kmDofKH1S6M1 Trop de connexions,
>     veuillez verifier votre configuration. Too many connections, slow
>     down. OFR004_104 [104])

We have problems with orange.fr/wanadoo.fr too. So much so that we 
created a separate postfix transport for it.

setup an orange_transport transport map:
orange.fr       orange:
.orange.fr      orange:
wanadoo.fr      orange:
.wanadoo.fr     orange:

create an orange transport in master.cf with 10 dedicated processes:
orange    unix  -       -       n       -       10      smtp


main.cf:
add orange_transport to transport_maps plus this

## orange
# they want us to limit to 3 but they have two MXs
# these limits are enforce per DOMAIN (not per transport)
orange_initial_destination_concurrency = 2
orange_destination_concurrency_limit = 2
orange_destination_recipient_limit = 50
orange_destination_rate_delay = 3s
# with a delay set we need to set failed cohort limit to prevent 
deferred mail
#  after a single error
orange_destination_concurrency_failed_cohort_limit = 50

This only helps some,  delivery is still often slow/bouncy.

This shows the hazard of trying to block spam by rate limiting inbound 
smtp connections, you end up blocking legit mail from mailing list servers.

Microsoft is a whole other set of problems...

--
Matt Taggart
address@concealed