the vendored dns resolver code is a copy of the go stdlib dns resolver, with
awareness of the "authentic data" (i.e. dnssec secure) added, as well as support
for enhanced dns errors, and looking up tlsa records (for dane). ideally it
would be upstreamed, but the chances seem slim.
dnssec-awareness is added to all packages, e.g. spf, dkim, dmarc, iprev. their
dnssec status is added to the Received message headers for incoming email.
but the main reason to add dnssec was for implementing dane. with dane, the
verification of tls certificates can be done through certificates/public keys
published in dns (in the tlsa records). this only makes sense (is trustworthy)
if those dns records can be verified to be authentic.
mox now applies dane to delivering messages over smtp. mox already implemented
mta-sts for webpki/pkix-verification of certificates against the (large) pool
of CA's, and still enforces those policies when present. but it now also checks
for dane records, and will verify those if present. if dane and mta-sts are
both absent, the regular opportunistic tls with starttls is still done. and the
fallback to plaintext is also still done.
mox also makes it easy to setup dane for incoming deliveries, so other servers
can deliver with dane tls certificate verification. the quickstart now
generates private keys that are used when requesting certificates with acme.
the private keys are pre-generated because they must be static and known during
setup, because their public keys must be published in tlsa records in dns.
autocert would generate private keys on its own, so had to be forked to add the
option to provide the private key when requesting a new certificate. hopefully
upstream will accept the change and we can drop the fork.
with this change, using the quickstart to setup a new mox instance, the checks
at internet.nl result in a 100% score, provided the domain is dnssec-signed and
the network doesn't have any issues.
we already do acme tls-alpn-01 validation, and still require it (we could relax
this at some point). http-01 is easy to add.
the bug was that the list of acme managers and hosts to refresh was overwritten
by another listener. the listeners are a map, and we range over it, so the
order we handle them is random. if the public listener was handled first, and
an internal handler later, the list was reset again.
- serve static files, serving index.html or optionally listings for directories
- redirects
- reverse-proxy, forwarding requests to a backend
these are configurable through the config file. a domain and path regexp have to
be configured. path prefixes can be stripped. configured domains are added to
the autotls allowlist, so acme automatically fetches certificates for them.
all webserver requests now have (access) logging, metrics, rate limiting.
on http errors, the error message prints an encrypted cid for relating with log files.
this also adds a new mechanism for example config files.
