Network
DNS
cat /etc/resolv.conf
DNS Record
RR: DNS Resource Record
A DNS zone file contains the list of all Resource Records in the DNS zone. Format is defined in RFC1035 page 33 with an addendum in RFC2308. A unique SOA RR and at least one NS RR for the zone name are required. A complete RR is a quintuplet {FQDN_NAME, TTL, CLASS, TYPE, RDATA} which can be in abbreviated form in some cases.
Comments start with a semicolon
;
and go to the end of line.Empty lines are allowed; any combination of tabs and spaces acts as a delimiter.
RR are defined line by line as :
[Name] [TTL] [CLASS] TYPE RDATA
if no
Name
, the name is taken from the last stated RRif
Name
exists, it starts at the first character of the lineif
Name
is not dot-terminated (non FQDN), the default domain name defined by$ORIGIN
directives is concatenated toName
if no
TTL
, the TTL is defined by$TTL
directives.if no
CLASS
, the CLASS is taken from the last stated RR
TTL
andCLASS
can be exchanged.
$TTL integer_value
sets the default value of TTL for following RRs in file (RFC2308, bind>8.1)
$ORIGIN fqdn_name
sets the default value of domain name for following RRs in file. Initially, in BIND, the value is set to the current zone name.
$INCLUDE filename
inserts the named file into the current file. NB: be careful about value of$TTL
or$ORIGIN
after a$INCLUDE
@
is used to denote the current default domain name.
(
and)
are used to group data that crosses a line boundary. Line terminations are not recognized within parentheses
\
is used to quote special characters. Ex :\.
can be used to place a dot character in a label;\223
is the 8-bit character corresponding to decimal value 223.Stylistic hints:
Organize RR : Start with SOA, NS and MX of the zone, continue with delegation (NS) and glue. Group RR by names.
Comments are useful
Use spaces or tabulations for vertical alignment
Start file with a
$ORIGIN
and a$TTL
Try to avoid writing of the zone name in the file
Generate serial number in SOA as : year/month/day/version 4+2+2+2.
BE CAREFUL: Modify the serial number each time the master file is modified
CNAME
can't be used for apex domain (aka bare domain or naked domain, ex: example.com):
See also:
Frequent Questions: DNS Records — Gandi Documentation documentation - DNS records exampels
Wake-on-LAN
IP address
0: 127.0.0.1 (or 0.0.0.0 on macOS)
10.50.1: 10.50.0.1
10.0.513: 10.0.2.1
167772673: 10.0.2.1
A000201: 10.0.2.1
10.0.2.010: 10.0.2.8
http://1089053027 is translated to http://64.233.161.99/ (then the server redirect to Google Search homepage) 32-bit url 0x1000000111010011010000101100011 == 1089053027 == (64 << 24) + (233 << 16) + (161 << 8) + 99
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