DESCRIPTION
tinydns-data reads local DNS information from a file named data in the
current directory. It creates data.cdb in a binary format designed for
fast access by tinydns. It may also create some other files with names
beginning with data.
tinydns-data updates data.cdb atomically, so you can use it safely
while tinydns is running. If anything goes wrong with the creation of
data.cdb, tinydns-data stops and leaves the old data.cdb in place.
Data format
The DNS information in data is a series of lines. There are several
types of lines, as shown below.
Each line starts with a special character and continues with a series
of vertical-bar separated fields. In some cases the fields may be
omitted; however, all vertical-bars must be included except at the end
of the line. Spaces and tabs at the end of a line are ignored.
Each line contains a ttl (``time to live'') specifying the number of
seconds that the line's DNS records may be cached. Beware that cache
times below 300 seconds will be treated as 300 by some clients, and NS
cache times below 2 seconds can cause lookup failures. You may omit
ttl;
tinydns-data will use default cache times, carefully selected to work
well in normal situations.
You may include a timestamp on each line. If ttl is nonzero (or
omitted), the timestamp is a starting time for the information in the
line; the line will be ignored before that time. If ttl is zero, the
timestamp is an ending time (``time to die'') for the information in
the line;
tinydns dynamically adjusts ttl so that the line's DNS records are not
cached for more than a few seconds past the ending time. A timestamp
is an external TAI64 timestamp, printed as 16 lowercase hexadecimal
characters. For example, the lines
+www.heaven.af.mil|1.2.3.4|0|4000000038af1379
+www.heaven.af.mil|1.2.3.7||4000000038af1379
specify that www.heaven.af.mil will have address 1.2.3.4 until time
4000000038af1379 (2000-02-19 22:04:31 UTC) and will then switch to IP
address 1.2.3.7.
A ``split-horizon'' mode is supported specifying client locations by %
lines followed by the IPv4 or IPv6 compactified adddress together with a
netprefix in CIDR notation:
%lo|ip/prefix
means that IP addresses starting with ip/prefix are in location lo. lo
is a sequence of two ASCII letters. A client is in only one lo-
cation; longer prefixes override shorter prefixes. For Example,
%in|192.168./16
%ex
+jupiter.heaven.af.mil|192.168.1.2|||in
+jupiter.heaven.af.mil|1.2.3.4|||ex
specifies that jupiter.heaven.af.mil has address 192.168.1.2 for
clients in the 192.168/16 subnet and address 1.2.3.4 for everyone
else.
Common data lines
=> .fqnd|ip|x|ttl|timestamp|lo
Name server for our domain fqdn.
tinydns-data creates
an NS record showing x.ns.fqdn as a name server for fqdn and
an A record showing ip as it's IPv4 address or an AAAA record
showing ip as the IPv6 address of x.ns.fqdn; and
an SOA record for fqdn listing x.ns.fqdn as the primary name server
and hostmaster@fqdn as the contact address.
You may have several name servers for one domain, with a different x
for each server.
tinydns will return only one SOA record per domain.
If x contains a dot then tinydns-data will use x as the server name
rather than x.ns.fqdn. This feature is provided only for compatibility
reasons; names not ending with fqdn will force clients to contact
parent servers much more often than they otherwise would, and will
reduce the overall reliability of DNS. You should omit ip if x has IP
addresses assigned elsewhere in data; in this case, tinydns-data will
omit the A or AAAA record.
=> &fqdn|ip|x|ttl|timestamp|lo
Name server for domain fqdn.
Normally & is used for domains delegated by this server to child
servers, while . is used for domains delegated to this server.
tinydns will return only one SOA record per domain.
If x contains a dot then tinydns-data will use x as the server name
rather than x.ns.fqdn. This feature is provided only for compatibility
reasons; names not ending with fqdn will force clients to contact
parent servers much more often than they otherwise would, and will
reduce the overall reliability of DNS. You should omit ip if x has IP
addresses assigned elsewhere in data; in this case, tinydns-data will
omit the A or AAAA record.
=> &fqdn|ip|x|ttl|timestamp|lo
Name server for domain fqdn.
tinydns-data creates
an NS record showing x.ns.fqdn as a name server for fqdn and
an A record ip as IPv4 or an AAAA record showing ip as the IPv6
address of x.ns.fqdn.
If x contains a dot then it is treated specially; see above.
You may have several name servers for one domain, with a different x
for each server.
Normally & is used for domains delegated by this server to child
servers, while . is used for domains delegated to this server.
=> =fqdn|ip|ttl|timestamp|lo
=> :fqdn|ip|ttl|timestamp|lo
Host fqdn with IPv4 or IPv6 address ip depending, whether the first
character is = or :.
tinydns-data creates
=> +fqdn|ip|ttl|timestamp|lo
=> ~fqdn|ip|ttl|timestamp|lo
Alias fqdn with IPv4 address ip in case the first character is + or an
IPv6 address if ~ is supplied. This is just like =fqdn|ip|ttl except
that tinydns-data does not create the PTR record.
tinydns returns addresses (from + or = or @ or . or & or : or ~ lines)
in a random order in the answer section.
If there are more than 8 records, it returns a random set of 8.
=> @fqdn|ip|x|dist|ttl|timestamp|lo
Mail exchanger for fqdn.
tinydns-data creates
an MX record showing x.mx.fqdn as a mail exchanger for fqdn at
distance dist and
an A or AAAA record showing ip as the IPv4 or IPv6 address of
x.mx.fqdn.
You may omit dist; the default distance is 0.
If x contains a dot then it is treated specially; see above.
You may create several MX records for fqdn, with a different x for each
server. Make sure to arrange for the SMTP server on each IP address to
accept mail for fqdn.
=> #comment
Comment line. The line is ignored.
Uncommon data lines
=> -fqdn|s|ttl|timestamp|lo
This type of line is used by programs that automatically edit + lines
in data to temporarily exclude addresses of overloaded or dead
machines. The line is ignored.
=> 'fqdn|s|ttl|timestamp|lo
TXT record for fqdn.
tinydns-data creates
a TXT record for fqdn containing the string s.
Printable ASCII characters - including white spaces - are accepted
unaltered.
=> Dfqdn|pubkey|selector|sigalg|hash|service|type|ttl|timestamp|lo
DKIM TXT record for fqdn.
tinydns-data creates
a DKIM TXT record according to RFC 6376 for fqdn.
pubkey is the representation of the public key while
selector is the optional domain selector prepending _domainkey
as additional label (mainly for key roll-over) yielding
selector._domainkey.fqdn.
sigalg is the optional signature algorithim defaulting to rsa while
hash is the given hash algorithm for the signature defaulting to sha256
but could be sha1 instead.
service covers the Internet service the DKIM signature is used for.
Here, it defaults to * (all services) while email could be possible as
well.
type is the optional type tag.
=> _fqdn|u|s|fingerprint|x|port|proto|ttl|timestamp|lo
TLSA record for fqdn.
tinydns-data creates
a TLSA record according to RFC 6698/7218/7671 for fqdn.
u denotes its usage and s the provided selector. In case s =Â 0 is set,
the fingerprint covers the full X.509 certificate, while for s = 1 it
is the hash of the public key (Subject Public Key Info) SPKI. Note:
According to RFC 6698 `plain` X.509 certs shall not be used here;
though tinydns allows this in principal.
tinydns defaults to u=3 and s=0, thus they don't need to be
provided. The required TLSA matching type parameter is automatically
calculated from the fingerprint's length.
The TLSA base domain is synthesized from the values fqdn, x, proto and
port yielding a final domain name _port._proto.x.fqdn. In case those
values are missing, automatically the following entry is generated:
_25._tcp.mail.fqdn. However, a typical choice for x is a.mx or b.mx.
If x starts with _ it is taken unaltered prepending fqdn.
=> ^fqdn|p|ttl|timestamp|lo
PTR record for fqdn.
tinydns-data creates
a PTR record for fqdn pointing to the domain name p.
=> Cfqdn|p|ttl|timestamp|lo
CNAME record for fqdn.
tinydns-data creates
Here, the first . is converted to @ as the contact address, ser as the
serial number, ref as the refresh time, ret as the retry time, exp as
the expire time, and min as the minimum time. ser, ref, ret, exp, and
min may be omitted; they default to, respectively, the modification
time of the data file, 16384 seconds, 2048 seconds, 1048576 seconds,
and 2560 seconds.
=> Ofqdn|n|rdata|ttl|timestamp|lo
Generic record for fqdn.
tinydns-data creates
a record of type n for fqdn showing rdata.
n must be an integer between 1 and 65535. The proper format of rdata
depends on n. You may use octal nnn codes to include arbitrary bytes
inside rdata.
WILDCARDS
tinydns supports wildcards of the form *.fqdn. Information for *.fqdn
is provided for every name ending with .fqdn, except names that have
their own records and names that are covered by more specific
wildcards.
For example, the lines
+pink.floyd.u.heaven.af.mil|1.2.3.4
+*.u.heaven.af.mil|1.2.3.200
have the same effect as
+pink.floyd.u.heaven.af.mil|1.2.3.4
+joe.u.heaven.af.mil|1.2.3.200
+bill.u.heaven.af.mil|1.2.3.200
+floyd.u.heaven.af.mil|1.2.3.200
+ishtar.u.heaven.af.mil|1.2.3.200
+joe.bob.u.heaven.af.mil|1.2.3.200
+sally.floyd.u.heaven.af.mil|1.2.3.200
+post.pink.floyd.u.heaven.af.mil|1.2.3.200
and so on.
Example for data file
Here is a typical data file:
=lion.heaven.af.mil|1.2.3.4
@heaven.af.mil|1.2.3.4
@3.2.1.in-addr.arpa|1.2.3.4
@heaven.af.mil|2001::25
=panther.heaven.af.mil|1.2.3.249
Here is the same information in traditional zone-file format (with the
two zones merged):
heaven.af.mil. 2560 IN SOA a.ns.heaven.af.mil. hostmaster.heaven.af.mil. ...
heaven.af.mil. 259200 IN NS a.ns.heaven.af.mil.
heaven.af.mil. 259200 IN NS b.ns.heaven.af.mil.
heaven.af.mil. 86400 IN MX mx.heaven.af.mil.
3.2.1.in-addr.arpa. 2560 IN SOA a.ns.3.2.1.in-addr.arpa. hostmaster.3.2.1.in-addr.arpa. ...
3.2.1.in-addr.arpa. 259200 IN NS a.ns.3.2.1.in-addr.arpa.
3.2.1.in-addr.arpa. 259200 IN NS b.ns.3.2.1.in-addr.arpa.
3.2.1.in-addr.arpa. 86400 IN MX mx.3.2.1.in-addr.arpa.
4.3.2.1.in-addr.arpa. 86400 IN PTR lion.heaven.af.mil.
lion.heaven.af.mil. 86400 IN A 1.2.3.4
mx.heaven.af.mil. 86400 IN A 1.2.3.4
mx.3.2.1.in-addr.arpa. 86400 IN A 1.2.3.4
5.3.2.1.in-addr.arpa. 86400 IN PTR tiger.heaven.af.mil.
tiger.heaven.af.mil. 86400 IN A 1.2.3.5
a.ns.heaven.af.mil. 259200 IN A 1.2.3.5
a.ns.3.2.1.in-addr.arpa. 259200 IN A 1.2.3.5
6.3.2.1.in-addr.arpa. 86400 IN PTR bear.heaven.af.mil.
bear.heaven.af.mil. 86400 IN A 1.2.3.6
b.ns.heaven.af.mil. 259200 IN A 1.2.3.6
b.ns.3.2.1.in-addr.arpa. 259200 IN A 1.2.3.6
248.3.2.1.in-addr.arpa. 86400 IN PTR cheetah.heaven.af.mil.
cheetah.heaven.af.mil. 86400 IN A 1.2.3.248
249.3.2.1.in-addr.arpa. 86400 IN PTR panther.heaven.af.mil.
panther.heaven.af.mil. 86400 IN A 1.2.3.249
DESIGN NOTES
The data format is very easy for programs to edit, and reasonably easy
for humans to edit, unlike the traditional zone-file format.
tinydns-data could support a name wherever an IP address is required;
it would look up the name in DNS and use the resulting address. This
would reliably track changes in offsite IP addresses if the database
were rebuilt periodically.
COMPATIBILTY
The used data format differs from DJB's convention for the following
declarations: : is used as IPv6 address identifier, while O is used as
token for arbitrary data instead of ':'. Thus, apart from this special
case, the resulting data.cdb is raw compatible; due to the different
token delimitor however not in binary format. Within the TXT mode "'"
octal codes are not supported; use octal representation 'O' instead.
8 djbdnscurve6:(tinydns-data)
Man(1) output converted with
man2html