DNS Records

A and AAAA

  • Stores IP address for a name
  • A --> IPv4
  • AAAA --> IPv6

CNAME (Alias)

  • Alias record for another record
  • Canonical name

MX Record

  • Mail exchange
  • Identifies mail server for DNS name
  • Has a priority associated with it
    • Lowest priority is tried first
    • Same priority --> random choice
  • When a mail delivery fails, next highest priority is tried next

SRV (Service Record)

  • Location of a service on the network
  • Contains:
    • Service (eg. LDAP)
    • Target
    • Port
    • Priority
  • Usually created automatically

SOA (Start of Authority)

  • One per zone
  • Primary name server for the zone
  • Email of admin
  • Serial number
  • Refresh time for a zone

NS (Name Server)

  • Contains authority DNS servers for domain
  • Can be DNS server with secondary zones
  • Best source to answer queries
    • Do not contain cached data

PTR (Pointer)

  • Used for reverse DNS lookups
  • Provides IP address --> name mapping
  • Opposite of A or AAAA records

Computer Science DNS Networking