dns.reverse(ip, callback) Performs a reverse DNS query that resolves an IPv4 or IPv6 address to an array of hostnames. The callback function has arguments (err, hostnames), where hostnames is an array of resolved hostnames for the given ip. On error, err is an Error object, where err.code is one of the DNS error codes.

dns.resolveSrv(hostname, callback) Uses the DNS protocol to resolve service records (SRV records) for the hostname. The addresses argument passed to the callback function will be an array of objects with the following properties: priority weight port name { priority: 10, weight: 5, port: 21223, name: 'service.example.com' }

dns.resolveSoa(hostname, callback) Uses the DNS protocol to resolve a start of authority record (SOA record) for the hostname. The addresses argument passed to the callback function will be an object with the following properties: nsname hostmaster serial refresh retry expire minttl { nsname: 'ns.example.com', hostmaster: 'root.example.com', serial: 2013101809, refresh: 10000, retry: 2400, expire: 604800, minttl: 3600 }

dns.resolveNs(hostname, callback) Uses the DNS protocol to resolve name server records (NS records) for the hostname. The addresses argument passed to the callback function will contain an array of name server records available for hostname (e.g., ['ns1.example.com', 'ns2.example.com']).

dns.resolveCname(hostname, callback) Uses the DNS protocol to resolve CNAME records for the hostname. The addresses argument passed to the callback function will contain an array of canonical name records available for the hostname (e.g. ['bar.example.com']).

dns.resolveMx(hostname, callback) Uses the DNS protocol to resolve mail exchange records (MX records) for the hostname. The addresses argument passed to the callback function will contain an array of objects containing both a priority and exchange property (e.g. [{priority: 10, exchange: 'mx.example.com'}, ...]).

dns.resolve6(hostname, callback) Uses the DNS protocol to resolve a IPv6 addresses (AAAA records) for the hostname. The addresses argument passed to the callback function will contain an array of IPv6 addresses.

dns.resolve(hostname[, rrtype], callback) Uses the DNS protocol to resolve a hostname (e.g. 'nodejs.org') into an array of the record types specified by rrtype. Valid values for rrtype are: 'A' - IPV4 addresses, default 'AAAA' - IPV6 addresses 'MX' - mail exchange records 'TXT' - text records 'SRV' - SRV records 'PTR' - used for reverse IP lookups 'NS' - name server records 'CNAME' - canonical name records 'SOA' - start of authority record The callback function has arguments (err,

dns.resolve4(hostname, callback) Uses the DNS protocol to resolve a IPv4 addresses (A records) for the hostname. The addresses argument passed to the callback function will contain an array of IPv4 addresses (e.g. ['74.125.79.104', '74.125.79.105', '74.125.79.106']).

dns.lookup(hostname[, options], callback) Resolves a hostname (e.g. 'nodejs.org') into the first found A (IPv4) or AAAA (IPv6) record. options can be an object or integer. If options is not provided, then IPv4 and IPv6 addresses are both valid. If options is an integer, then it must be 4 or 6. Alternatively, options can be an object containing these properties: family {Number} - The record family. If present, must be the integer 4 or 6. If not provided, both IP v4 and v6 addresses are accept