Implements a new mode "transport",
that allows filtermail to be used for
remote delivery.
In transport mode, filtermail listens for LMTP
connections, splits messages by domain
and performs delivery to remote MTAs over SMTP.
SMTP client tries to open socket on all resolved
addresses in parallel and uses one that succeeds
the first, fixing the issue described in:
chatmail/relay#900
Extends the built-in SMTP client
with STARTTLS support.
Extends the built-in SMTP server
with LMTP greeting support.
Groundwork required for mxdeliv endpoint
(HTTP channel for MTA-to-MTA communication):
chatmail/relay#900
Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>
BREAKING CHANGE: messages using domain-literal
addresses don't require to match the origin
SMTP connection IP anymore.
Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>
If the MAIL FROM doesn't match the From header,
we do not reject the mail, as this can be caused
by e.g. SRS forwarding. Instead, we reset the envelope
address, so it is reinjected as `MAIL FROM:<>`
to prevent sending a bounce message.
Closes#67
Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>
This way we won't be logging DKIM rejections on messages that
would be rejected anyway due to not being encrypted.
Fixes#69
Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>
`String::from_utf8_lossy` always copies the data
for the case when it needs to replace invalid UTF-8,
but we don't want invalid UTF-8 anyway as replacing
invalid UTF-8 characters will break DKIM signature.
Previously header parsing caused leading whitespaces to be
trimmed in HeaderBody, which resulted in incorrect simple
header canonicalization.
Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>
If the incoming email comes from address that uses
domain literals `[<ipv4>]` or `[IPv6:<ipv6>]`,
skip DKIM verification and instead check IP
alignment with originating IP from XFORWARD
command.
Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>
* feat!: DKIM verifier
This implements a DKIM verification as well as a strict
DKIM signature alignment check with domain in `From`
header address.
Caches the retrieved RDATA using in-memory LRU.
BREAKING CHANGE: incoming messages now require DKIM signatures
aligned to domain of the `From` header address.
Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>
* chore(license): License binaries under GPLv3
Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>
---------
Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>
