Oracle Cloud Infrastructure Documentation

How to Format a Zone File

A zone file is a text file that describes a DNS zone. The BIND file format is the industry preferred zone file format and has been widely adopted by DNS server software. The format is defined in RFC 1035.

Example of a Zone File

This is an example of a zone file downloaded from Oracle Cloud Infrastructure DNS.

$ORIGIN example.com.
			@                    3600 SOA   ns1.p30.oraclecloud.net. (
			zone-admin.dyndns.com.     ; address of responsible party
			2016072701                 ; serial number
			3600                       ; refresh period
			600                        ; retry period
			604800                     ; expire time
			1800                     ) ; minimum ttl
			86400 NS    ns1.p68.dns.oraclecloud.net.
			86400 NS    ns2.p68.dns.oraclecloud.net.
			86400 NS    ns3.p68.dns.oraclecloud.net.
			86400 NS    ns4.p68.dns.oraclecloud.net.
			3600 MX    10 mail.example.com.
			3600 MX    20 vpn.example.com.
			3600 MX    30 mail.example.com.
			60 A     204.13.248.106
			3600 TXT   "v=spf1 includespf.oraclecloud.net ~all"
			mail                  14400 A     204.13.248.106
			vpn                      60 A     216.146.45.240
			webapp                   60 A     216.146.46.10
			webapp                   60 A     216.146.46.11
		www                   43200 CNAME example.com.

 

Note

Record Classes

In the example zone file above, no record classes are displayed. Oracle Cloud Infrastructure DNS only works with Internet (IN) class records but omits the class information in zone files for efficiency purposes.

Anatomy of a Zone File

$ORIGIN indicates a DNS node tree and will typically start a DNS zone file. Any host labels below the origin will append the origin hostname to assemble a fully qualified hostname. Any host label within a record that uses a fully qualified domain terminating with an ending period will not append the origin hostname.

Example: With $ORIGIN example.com., any record where the host label field is not followed by a period, example.com. will be appended to them.

The “@” symbol is a special label that indicates the $ORIGIN should replace the “@” symbol. This is typically used for the apex of a zone.

SOA Record – The $ORIGIN is followed by the zone’s Start Of Authority (SOA) record. An SOA record is required for each zone. It contains the name of the zone, the e-mail address of the party responsible for administering the domain’s zone file, the current serial number of the zone, the primary nameserver of the zone, and various timing elements (measured in seconds).

SOA Record Format

@     IN     SOA    {primary-name-server}     {hostmaster-email} (
				{serial-number}
				{time-to-refresh}
				{time-to-retry}
				{time-to-expire}
			{minimum-TTL} )
  • Primary Name Server – The nameserver that contains the original zone file and not an AXFR transferred copy.
  • Hostmaster Email – Address of the party responsible for the zone. A period “.” is used in place of an “@” symbol. For email addresses that contain periods, replace the periods with a slash “/”.
  • Serial Number – Version number of the zone. The serial number will increase with each subsequent update to your zone.
  • Time To Refresh – How long a nameserver should wait prior to checking for a serial number increase within the primary zone file, in seconds. An increased serial number detected by a secondary DNS nameserver means a transfer is needed to sync your records. Only applies to zones using secondary DNS.
  • Time To Retry – How long a nameserver should wait prior to retrying to update a zone after a failed attempt, in seconds. Only applies to zones using secondary DNS.
  • Time To Expire – How long a nameserver should wait prior to considering data from a secondary zone invalid and stop answering queries for that zone, in seconds. Only applies to zones using secondary DNS.
  • Minimum TTL – Minimum Time To Live (TTL). How long a nameserver or resolver should cache a negative response, in seconds.

Anatomy of a Record Within a Zone File

A zone file is a collection of resource records with each record entry described in the following sequence:

Format: Host Label TTL Record Class Record Type Record Data
Example: example.com. 60 IN A 104.255.228.125

  • Host Label – A host label helps to define the hostname of a record and whether the $ORIGIN hostname will be appended to the label. Fully qualified hostnames terminated by a period will not append the origin.
  • TTL – The Time To Live (TTL) is the amount of time that a DNS record will be cached by an outside DNS server or resolver, in seconds.
  • Record Class – There are three classes of DNS records: IN (Internet), CH (Chaosnet), and HS (Hesiod). Oracle Cloud Infrastructure DNS only uses the IN class of records.
  • Record Type – The type of a record, such as CNAME, AAAA, or TXT.
  • Record Data – The data within a DNS answer, such as an IP address, hostname, or other information. Different record types will contain different types of record data.

Amending Zone Files Exported from GoDaddy.com for Import

GoDaddy.com exports zone files in a proprietary format. To get the Oracle Cloud Infrastructure DNS service to correctly import a zone file exported from GoDaddy.com, you must directly alter the file. Follow these instructions to update the zone file.

  1. Export your zone file from GoDaddy.com. Reference GoDaddy.com's documentation to see how this is done.
  2. Open the file in your preferred text editor.
  3. Prepend a new line to the file before the SOA record with the following information, including the trailing period: $ORIGIN [yourdomain].
  4. Once the file has been amended, save the changes to the file and use the zone import function to import the file into your DNS configuration. For more information about zone import, see Managing DNS Zones.

Note

If your zone file includes includes dynamic A records, such as @ 600 IN A GoCentral Published Site, you will need to amend these records with the correct IP addresses of your website. Please contact GoDaddy.com for information about how to obtain this information.

Example:@ 600 IN A 192.0.2.255

Example:

This is an example of a zone file exported from GoDaddy.com. The code in bold is the code that needs to be removed from the file for it to be eligible for import into Oracle Cloud Infrastructure DNS.

Tip

Placing a semi-colon at the beginning of a line is valid comment syntax for a zone file, per RFC 1035, but for ease of use and formatting it is recommended to remove the large section of comments from the beginning of the zone file provided by GoDaddy.com, as shown below.

Domain: example.com
; Exported (y-m-d hh:mm:ss): 2019-01-10 13:05:04
;
; This file is intended for use for informational and archival
; purposes ONLY and MUST be edited before use on a production
; DNS server.
;
; In particular, you must update the SOA record with the correct
; authoritative name server and contact e-mail address information,
; and add the correct NS records for the name servers which will
; be authoritative for this domain.
;
; For further information, please consult the BIND documentation
; located on the following website:
;
; http://www.isc.org/
;
; And RFC 1035:
;
; http://www.ietf.org/rfc/rfc1035.txt
;
; Please note that we do NOT offer technical support for any use
; of this zone data, the BIND name server, or any other third-
; party DNS software.
;
; Use at your own risk.
; SOA Record
example.com.        3600     IN     SOA ns41.domaincontrol.com. dns.net. (
                    2018122702
                    28800
                    7200
                    604800
                    3600
                    ) 
; A Records
@   600  IN     A   192.0.2.249
blog    10800    IN     A   192.0.2.255
dev 1800     IN     A   192.0.2.254
dev01   1800     IN     A   192.0.2.253
dev02   1800     IN     A   192.0.2.252
dev03   1800     IN     A   192.0.2.251
dev04   1800     IN     A   192.0.2.250
; CNAME Records
abc123b432dc7785b7ef31f04f25c3e71    1800     IN     CNAME   verify.bing.com.
akamai  600  IN     CNAME   www.example.com.edgekey.net.
email   3600     IN     CNAME   email.secureserver.net.
; MX Records
@   604800   IN     MX  10  amlxe.l.google.com.
@   604800   IN     MX  10  aplxe.l.google.com.
; TXT Records
@   3600     IN     TXT "google-site-verification=3J82-80dbMyCo5Q5C1G11JszeOnZPGCSYlHcPcXg"
@   3600     IN     TXT "google-site-verification=eS_QPYLE_W4nduSrlN-cddxG7ZqOnB743xsbX918"

 

Below is an example of an amended zone file ready to import into Oracle Cloud Infrastructure DNS. The code in bold needs to be prepended to your zone file before import.

$ORIGIN example.com.
example.com.	     3600     IN     SOA ns41.domaincontrol.com. dns.net. (
                    2018122702
                    28800
                    7200
                    604800
                    3600
		     )
					
; A Records
@   600  IN     A   192.0.2.249
blog    10800    IN     A   192.0.2.255
dev 1800     IN     A   192.0.2.254
dev01   1800     IN     A   192.0.2.253
dev02   1800     IN     A   192.0.2.252
dev03   1800     IN     A   192.0.2.251
dev04   1800     IN     A   192.0.2.250abc123b432dc7785b7ef31f04f25c3e71    1800     IN     CNAME   verify.bing.com.
; CNAME Records
akamai  600  IN     CNAME   www.example.edgekey.net.
email   3600     IN     CNAME   email.secureserver.net.
; MX Records
@   604800   IN     MX  10  amlxe.l.google.com.
@   604800   IN     MX  10  aplxe.l.google.com.
; TXT Records
@   3600     IN     TXT "google-site-verification=3J82-80dbMyCo5Q5C1GM8os1VYVEOnZPGCSYlHcPcXg"
@   3600     IN     TXT "google-site-verification=eS_QPYLE_W4nduSrlN-cddxG7ZqOnB7k7uIG7qrsyu8"