mDNS (Multicast DNS)

Low Risk

UDP — DNS

Port Overview

Port Number 5353

Service Name mDNS (Multicast DNS)

Transport Protocol UDP

Category DNS

Security Risk Low

Port Range Registered (1024-49151)

What is Port 5353?

Port 5353 is used by mDNS (Multicast DNS), which enables zero-configuration DNS name resolution on local networks without a central DNS server. Apple's Bonjour and Linux's Avahi implement mDNS to allow devices to discover services like printers, AirPlay, and Chromecast. Queries and responses are sent to the multicast address 224.0.0.251.

UDP DNS Commonly Used

Security Considerations

Port 5353 (mDNS (Multicast DNS)) is classified as low risk. This service uses encryption or has a minimal attack surface, making it relatively safe to expose.

Recommendation: Standard security practices apply. Keep software updated and monitor access.

Related Ports — DNS

42 WINS / nameserver 53 DNS 101 NIC Host Name 853 DNS over TLS 953 RNDC 1512 WINS 2053 Knetd / DNS over TLS 5355 LLMNR (Link-Local Multicast Name Resolution)