DNS Resource Records
Each zonefile can contain many resource records.
|A||IPv4 Address record|
|AAAA||IPv6 Address record|
|CNAME||Canonical Name: a name (an alias) which redirects to another a host.|
|MX||Mail eXchange record: includes a preference value for the mail server.|
|PTR||PoinTeR record: used to reverse map? IP addresses to hostnames.|
|SOA||Start of Authority: provides the name of the zone, email address, and other data.|
|SRV||SeRVices record: lists the services available such as SIP, XMPP, LDAP, HTTP. This helps for discovering services.|
|TXT||TeXT record: any text can be provided with a name, such as an SPF record? or a DKIM record?|
Creating DNS records
Each record in the zone file is written in this format:
Name TTL Class Type Data
; zone file for example.com $TTL 2d ; 172800 secs default TTL for zone $ORIGIN example.com. @ IN SOA ns1.example.com. hostmaster.example.com. (
2003080800 ; se = serial number 12h ; ref = refresh 15m ; ret = update retry 3w ; ex = expiry 3h ; min = minimum ) IN NS ns1.example.com. IN MX 10 mail.example.net.
joe IN A 192.168.254.3 www IN CNAME joe