DNS Messages and Records

Summary

This chapter described the protocol messages that pass between DNS servers. This is sometimes called the wire format. In most cases the message, or wire, format can be interpreted using a packet sniffer—there are times, however, when even the best tools either don’t support the latest version or provide less-than-complete interpretation in which the user has to resort to tried and trusted manual methods. Each message has the same format comprising a message header followed by QUESTION, ANSWER, AUTHORITY, and ADDITIONAL SECTIONs. EDNS0 message formats add further complexity to the wire format but are only used with security transactions such as TSIG, SIG(0), TKEY, and DNSSEC.