SOA

SOA stand for Start Of Authority and is used in DNS network configuration files for named using Standard Resource Records to mark beginning of zone data. A typical SOA record looks like

@  IN    SOA  somehost.somedomain.sometld. username.somehost.somedomain.sometld. (               12345              ; serial                720000             ; refresh every 200 hours                1800               ; retry after 30 minutes                7200000            ; expire after 2000 hours                   900                ; negative cache is 15 minutes                )