Port 9091: Transmission

Port 9091 is the default web interface port for the Transmission BitTorrent client, letting you add and manage torrents from a browser. It is a convention set by the Transmission project rather than an IANA assignment.

TCPFile transferUnencrypted by default
Port number9091
ServiceTransmission BitTorrent client web UI
ProtocolTCP
CategoryFile transfer
Default encryptionNo
Security note. Port 9091 is not encrypted by default. Restrict it to trusted networks, or use an encrypted alternative where one exists, to avoid exposing credentials and data in transit.

Frequently asked questions

What is port 9091 used for?

Port 9091 is the default web interface port for the Transmission BitTorrent client, letting you add and manage torrents from a browser. It is a convention set by the Transmission project rather than an IANA assignment.

Is port 9091 TCP or UDP?

Port 9091 (Transmission) uses TCP.

Is port 9091 secure?

Port 9091 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.

Should I open port 9091 on my firewall?

Only if you specifically need Transmission. Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.