mox/vendor/github.com/mjl-/adns/doc.go

/*
adns is a copy of the Go standard library, modified to provide details about
the DNSSEC status of responses.

The MX, NS, SRV types from the "net" package are used to make to prevent churn
when switching from net to adns.

Modifications

  - Each Lookup* also returns a Result with the "Authentic" field representing if
    the response had the "authentic data" bit (and is trusted), i.e. was
    DNSSEC-signed according to the recursive resolver.
  - Resolver are also trusted if all name servers have loopback IPs. Resolvers
    are still also trusted if /etc/resolv.conf has "trust-ad" in the "options".
  - New function LookupTLSA, to support DANE which uses DNS records of type TLSA.
  - Support Extended DNS Errors (EDE) for details about DNSSEC errors.
  - adns uses its own DNSError type, with an additional "Underlying error" field
    and Unwrap function, so callers can check for the new ExtendedError type.
*/
package adns
implement dnssec-awareness throughout code, and dane for incoming/outgoing mail delivery 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. 2023-10-10 13:09:35 +03:00			`/*`
			`adns is a copy of the Go standard library, modified to provide details about`
			`the DNSSEC status of responses.`

			`The MX, NS, SRV types from the "net" package are used to make to prevent churn`
			`when switching from net to adns.`

			`Modifications`

			`- Each Lookup* also returns a Result with the "Authentic" field representing if`
			`the response had the "authentic data" bit (and is trusted), i.e. was`
			`DNSSEC-signed according to the recursive resolver.`
			`- Resolver are also trusted if all name servers have loopback IPs. Resolvers`
			`are still also trusted if /etc/resolv.conf has "trust-ad" in the "options".`
			`- New function LookupTLSA, to support DANE which uses DNS records of type TLSA.`
			`- Support Extended DNS Errors (EDE) for details about DNSSEC errors.`
			`- adns uses its own DNSError type, with an additional "Underlying error" field`
			`and Unwrap function, so callers can check for the new ExtendedError type.`
			`*/`
			`package adns`