Port 3128: Squid

Port 3128 is the traditional default port for the Squid caching proxy, widely used to filter, cache, and log outbound web traffic for a network. It is a long-standing convention rather than an IANA assignment.

TCPProxy & tunnelingUnencrypted by default
Port number3128
ServiceSquid caching proxy
ProtocolTCP
CategoryProxy & tunneling
Default encryptionNo
Security note. Port 3128 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 3128 used for?

Port 3128 is the traditional default port for the Squid caching proxy, widely used to filter, cache, and log outbound web traffic for a network. It is a long-standing convention rather than an IANA assignment.

Is port 3128 TCP or UDP?

Port 3128 (Squid) uses TCP.

Is port 3128 secure?

Port 3128 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.

Should I open port 3128 on my firewall?

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