Which protocol is used by DNS?

DNS uses TCP for Zone transfer and UDP for name, and queries either regular (primary) or reverse. UDP can be used to exchange small information whereas TCP must be used to exchange information larger than 512 bytes.

What are the messages exchanged in the DNS?

DNS messages are the data units that are transmit- ted between name servers and resolvers. The message for- mat (see figure 5) consists of a header, containing a num- ber of fixed fields that are always present, and up to four sections that carry query parameters and resource records.

Does DNS use UDP or TCP?

DNS has always been designed to use both UDP and TCP port 53 from the start 1 , with UDP being the default, and fall back to using TCP when it is unable to communicate on UDP, typically when the packet size is too large to push through in a single UDP packet.

What are the 3 types of DNS?

The three DNS server types server are the following:

  • DNS stub resolver server.
  • DNS recursive resolver server.
  • DNS authoritative server.

What are the types of DNS messages?

DNS has two types of messages: query and response. Both types have the same format. The query message consists of a header and question records; the response message consists of a header, question records, answer records, authoritative records, and additional records (see Figure4).

Is SIP UDP or TCP?

SIP can be carried by several transport layer protocols including Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Stream Control Transmission Protocol (SCTP). SIP clients typically use TCP or UDP on port numbers 5060 or 5061 for SIP traffic to servers and other endpoints.

What are the two types of DNS server?

There are three main kinds of DNS Servers — primary servers, secondary servers, and caching servers.

  • Primary Server. The primary server is the authoritative server for the zone.
  • Secondary Servers. Secondary servers are backup DNS Servers.
  • Caching Servers.