What does the acronym SOA stand for in networking?

• A. Single Origin Authority
• B. Start of Authority
• C. System Organization Agreement
• D. Secure Outside Access

Answer: (B)

SOA in networking stands for Start of Authority. In DNS, the SOA record is the authoritative data marker for a zone. It sits at the top of a zone file and defines who controls the zone—specifically the primary name server for the zone and the mailbox of the zone administrator. It also carries important timing information that tells secondary DNS servers how often to check for updates (refresh), what to do if an update isn’t received (retry), and how long results can be used if a server can’t refresh (expiry), along with the default minimum TTL for records in the zone. This combination of identifying the authoritative source and guiding synchronization between DNS servers is what makes Start of Authority the correct expansion. The other phrases don’t correspond to a standard DNS term and don’t describe the zone’s authoritative metadata.