link2xt a5b9a98baa fix: limit the number of LMTP clients for filtermail-transport to 1000
Postfix does not have jitter for deferred mails
and scans the queue periodically every
queue_run_delay (<https://www.postfix.org/postconf.5.html#queue_run_delay>).
As a result it is likely
to try delivering many deferred messages
at the same time.

Normally the number of outgoing connections
should be low even with unreachable destinations,
but after the server downtime
or if admin flushes the queue manually
it is possible that a lot of messages
to the same unreachable destination
expire at once and are moved
from "deferred" into the "active" queue.

Trying to deliver them all at once
may make the server run out of memory
by starting many LMTP clients.
Limiting the number of LMTP processes
turns OOM problem into head of line blocking problem.
Messages sent to reachable destinations
will be delayed as well,
but at least deferred messages will
get distributed over time.

In this case "active" queue may grow
(up to qmgr_message_active_limit defaulting to 20000),
but then admin may notice the problem
and solve it e.g. by making the destinations reachable
or setting up a transport map to route
messages for known dead servers into discard transport.

Eventually the problem should be solved
by filtermail-transport quickly returning temporary errors
for destinations which already have many messages queued,
then we can reduce "maxproc" further.
2026-05-19 22:17:04 +00:00
2025-12-18 09:21:19 +01:00

Chatmail relays for end-to-end encrypted email

Chatmail relay servers are interoperable Mail Transport Agents (MTAs) designed for:

  • Zero State: no private data or metadata collected, messages are auto-deleted, low disk usage

  • Instant/Realtime: sub-second message delivery, realtime P2P streaming, privacy-preserving Push Notifications for Apple, Google, and Huawei;

  • Security Enforcement: only strict TLS, DKIM and OpenPGP with minimized metadata accepted

  • Reliable Federation and Decentralization: No spam or IP reputation checks, federating depends on established IETF standards and protocols.

This repository contains everything needed to setup a ready-to-use chatmail relay on an ssh-reachable host. For getting started and more information please refer to the web version of this repositories' documentation at

https://chatmail.at/doc/relay

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