NAME | SYNOPSIS | DESCRIPTION | POSITIVE TRUST ANCHORS | NEGATIVE TRUST ANCHORS | SEE ALSO | NOTES | COLOPHON

DNSSEC-TRUST-ANCHORS.D(5)  dnssec-trust-anchors.d  DNSSEC-TRUST-ANCHORS.D(5)

NAME         top

       dnssec-trust-anchors.d, systemd.positive, systemd.negative - DNSSEC
       trust anchor configuration files

SYNOPSIS         top

       /etc/dnssec-trust-anchors.d/*.positive

       /run/dnssec-trust-anchors.d/*.positive

       /usr/lib/dnssec-trust-anchors.d/*.positive

       /etc/dnssec-trust-anchors.d/*.negative

       /run/dnssec-trust-anchors.d/*.negative

       /usr/lib/dnssec-trust-anchors.d/*.negative

DESCRIPTION         top

       The DNSSEC trust anchor configuration files define positive and
       negative trust anchors systemd-resolved.service(8) bases DNSSEC
       integrity proofs on.

POSITIVE TRUST ANCHORS         top

       Positive trust anchor configuration files contain DNSKEY and DS
       resource record definitions to use as base for DNSSEC integrity
       proofs. See RFC 4035, Section 4.4[1] for more information about
       DNSSEC trust anchors.

       Positive trust anchors are read from files with the suffix .positive
       located in /etc/dnssec-trust-anchors.d/, /run/dnssec-trust-anchors.d/
       and /usr/lib/dnssec-trust-anchors.d/. These directories are searched
       in the specified order, and a trust anchor file of the same name in
       an earlier path overrides a trust anchor files in a later path. To
       disable a trust anchor file shipped in
       /usr/lib/dnssec-trust-anchors.d/ it is sufficient to provide an
       identically-named file in /etc/dnssec-trust-anchors.d/ or
       /run/dnssec-trust-anchors.d/ that is either empty or a symlink to
       /dev/null ("masked").

       Positive trust anchor files are simple text files resembling DNS zone
       files, as documented in RFC 1035, Section 5[2]. One DS or DNSKEY
       resource record may be listed per line. Empty lines and lines
       starting with a semicolon (";") are ignored and considered comments.
       A DS resource record is specified like in the following example:

           . IN DS 19036 8 2 49aac11d7b6f6446702e54a1607371607a1a41855200fd2ce1cdde32f24e8fb5

       The first word specifies the domain, use "."  for the root domain.
       The domain may be specified with or without trailing dot, which is
       considered equivalent. The second word must be "IN" the third word
       "DS". The following words specify the key tag, signature algorithm,
       digest algorithm, followed by the hex-encoded key fingerprint. See
       RFC 4034, Section 5[3] for details about the precise syntax and
       meaning of these fields.

       Alternatively, DNSKEY resource records may be used to define trust
       anchors, like in the following example:

           . IN DNSKEY 257 3 8 AwEAAagAIKlVZrpC6Ia7gEzahOR+9W29euxhJhVVLOyQbSEW0O8gcCjFFVQUTf6v58fLjwBd0YI0EzrAcQqBGCzh/RStIoO8g0NfnfL2MTJRkxoXbfDaUeVPQuYEhg37NZWAJQ9VnMVDxP/VHL496M/QZxkjf5/Efucp2gaDX6RS6CXpoY68LsvPVjR0ZSwzz1apAzvN9dlzEheX7ICJBBtuA6G3LQpzW5hOA2hzCTMjJPJ8LbqF6dsV6DoBQzgul0sGIcGOYl7OyQdXfZ57relSQageu+ipAdTTJ25AsRTAoub8ONGcLmqrAmRLKBP1dfwhYB4N7knNnulqQxA+Uk1ihz0=

       The first word specifies the domain again, the second word must be
       "IN", followed by "DNSKEY". The subsequent words encode the DNSKEY
       flags, protocol and algorithm fields, followed by the key data
       encoded in Base64. See RFC 4034, Section 2[4] for details about the
       precise syntax and meaning of these fields.

       If multiple DS or DNSKEY records are defined for the same domain
       (possibly even in different trust anchor files), all keys are used
       and are considered equivalent as base for DNSSEC proofs.

       Note that systemd-resolved will automatically use a built-in trust
       anchor key for the Internet root domain if no positive trust anchors
       are defined for the root domain. In most cases it is hence
       unnecessary to define an explicit key with trust anchor files. The
       built-in key is disabled as soon as at least one trust anchor key for
       the root domain is defined in trust anchor files.

       It is generally recommended to encode trust anchors in DS resource
       records, rather than DNSKEY resource records.

       If a trust anchor specified via a DS record is found revoked it is
       automatically removed from the trust anchor database for the runtime.
       See RFC 5011[5] for details about revoked trust anchors. Note that
       systemd-resolved will not update its trust anchor database from DNS
       servers automatically. Instead, it is recommended to update the
       resolver software or update the new trust anchor via adding in new
       trust anchor files.

       The current DNSSEC trust anchor for the Internet's root domain is
       available at the IANA Trust Anchor and Keys[6] page.

NEGATIVE TRUST ANCHORS         top

       Negative trust anchors define domains where DNSSEC validation shall
       be turned off. Negative trust anchor files are found at the same
       location as positive trust anchor files, and follow the same
       overriding rules. They are text files with the .negative suffix.
       Empty lines and lines whose first character is ";" are ignored. Each
       line specifies one domain name which is the root of a DNS subtree
       where validation shall be disabled.

       Negative trust anchors are useful to support private DNS subtrees
       that are not referenced from the Internet DNS hierarchy, and not
       signed.

       RFC 7646[7] for details on negative trust anchors.

       If no negative trust anchor files are configured a built-in set of
       well-known private DNS zone domains is used as negative trust
       anchors.

       It is also possibly to define per-interface negative trust anchors
       using the DNSSECNegativeTrustAnchors= setting in systemd.network(5)
       files.

SEE ALSO         top

       systemd(1), systemd-resolved.service(8), resolved.conf(5),
       systemd.network(5)

NOTES         top

        1. RFC 4035, Section 4.4
           https://tools.ietf.org/html/rfc4035#section-4.4

        2. RFC 1035, Section 5
           https://tools.ietf.org/html/rfc1035#section-5

        3. RFC 4034, Section 5
           https://tools.ietf.org/html/rfc4034#section-5

        4. RFC 4034, Section 2
           https://tools.ietf.org/html/rfc4034#section-2

        5. RFC 5011
           https://tools.ietf.org/html/rfc5011

        6. IANA Trust Anchor and Keys
           https://data.iana.org/root-anchors/root-anchors.xml

        7. RFC 7646
           https://tools.ietf.org/html/rfc7646

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
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       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have a bug
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systemd 234                                        DNSSEC-TRUST-ANCHORS.D(5)

Pages that refer to this page: resolved.conf(5)systemd.directives(7)systemd.index(7)systemd-resolved.service(8)