Protocols used for communicating data across a packet-switched internet work using the Internet Protocol Suite, also referred to as TCP/IP.
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Multicast DNS (mDNS) is a protocol that uses similar APIs to the normal unicast Domain Name System but implemented differently. Each computer on the LAN stores its own list of DNS resource records (e.g. A, MX, SRV, etc) and when an mDNS client wants to know the IP address of a PC given its name, the PC with the corresponding A record replies with its IP address.
