This illustration uses a series of bars to represent and explain the various fields in a DNS message. These bars are labeled according to what they contain, and are stacked one on top of the other. From top to bottom, we see:
The header section, denoted as comprising 12 bytes.
| Identification | Flags |
| Number of questions | Number of answer RRs |
| Number of authority RRs | Number of additional RRs |
The question section, denoted as containing "Name, type fields for a query."
| Questions |
| (variable number of questions) |
The answer section, denoted as containing "RRs in response to query."
| Answers |
| (variable number of resource records) |
The authority section, denoted as containing "Records for authoritative servers."
| Authority |
| (variable number of resource records) |
The additional section, denoted as containing "Additional 'helpful' info that may be used."
| Additional information |
| (variable number of resource records) |