Formatting a DNS Zone File

Service Limits

The Oracle Cloud Infrastructure DNS service is limited to 1000 zones per account and 25,000 records per zone. Customers with zone and record size needs exceeding these values are encouraged to contact support at support.oracle.com.

Zone File Limits

Zone file uploads are limited to 1 megabyte (MB) in size per zone file.

To work around this limitation, first use either the console or the CreateZone API operation to create a zone. Then, use the PatchDomainRecords API operation to add records to the zone in batches of 100.

Import and Export Limits

Exporting zone files containing ALIAS record types or that use Traffic Management (TM) isn't supported. This is because zone files are exported as RFC standard records, and ALIAS records and TM are nonstandard record types. You can use the GetZoneRecords API operation to obtain a backup of nonstandard records. Use the limit parameter to create batches of 100 records each.

Import and export for global zones is supported in both the Console and API, except for ALIAS and TM records.

For private zones, import is supported using the CreateZone API operation. Zone export isn't supported.

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.

$ORIGIN indicates a DNS node tree and typically starts a DNS zone file. Any host labels following the origin append the origin hostname to assemble a fully qualified hostname. Any host label within a record that uses a fully qualified domain name ending with a period isn't append the origin hostname.

Example: With ORIGIN example.com., any record where the host label field isn't followed by a period, example.com. is appended to them.

The "@" symbol is a special label that indicates the $ORIGIN needs to 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-for-negative-cache} )

• 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 increases with each following update to the zone.
• Time To Refresh – How long a nameserver waits before 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 the records. Only applies to zones using secondary DNS.
• Time To Retry – How long a nameserver waits before retrying to update a zone after a failed try, in seconds. Only applies to zones using secondary DNS.
• Time To Expire – How long a nameserver waits before considering data from a secondary zone invalid and to 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 caches a negative response, in seconds.

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

• Host Label – A host label helps to define the hostname of a record and whether the $ORIGIN hostname is appended to the label. Fully qualified hostnames terminated by a period aren't append the origin.
• TTL – The Time To Live (TTL) is the amount of time that a DNS record is cached by an outside DNS server or resolver, in seconds.
• Record Class – Three classes of DNS records exist: 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 contain different types of record data.

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

1. Export the zone file from GoDaddy. Reference GoDaddy's documentation to see how this is done.
2. Open the file in any 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. After the file has been amended, save the changes to the file and use the zone import function to import the file into the DNS configuration. For more information about zone import, see Managing DNS Zones.

Example:

This is an example of a zone file exported from GoDaddy. 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.

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"

The following example shows an amended zone file ready to import into OCI DNS. The code in bold needs to be prepended to the 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"