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Port 853: DNS over TLS

Common Ports Reference: What runs on port 3389, 445 or 5985: common TCP and UDP ports for web, mail, Windows, AD, databases and VPNs, with security notes.

The ports that come up when opening a firewall, reading a scan or troubleshooting a connection: what runs on each, TCP or UDP, and what to watch out for. Search by number or name. Port numbers and service names were checked against IANA's port number registry; ports that are widely used but assigned by IANA to something else are marked unofficial.

Port number or name

853 is a system port (0-1023): assigned by IANA, and on Linux only root can listen on it. IANA's registry lists everything assigned to it: look up 853 at IANA.

1 of 96 ports

DNS, DHCP, time, SNMP, logging and VPNs.

PortProtocolServiceWhat it's forIANA name
853
TCP
DNS over TLS
Encrypted DNS (DoT), used by Android Private DNS and many resolvers. DNS over HTTPS uses 443.
domain-s

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