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