What it does
OpenSnitch is a GNU/Linux application firewall with interactive outgoing-connection control, domain blocklists and multi-node management.
OpenSnitch is useful when the question is which Linux application initiated a connection. Its README describes interactive outbound filtering and a graphical interface that can manage several nodes. Review normal application behavior before making a broad deny policy. Domain blocking and system-firewall rules have different scopes from a single app exception. Keep a record of why an exception exists so later connection prompts do not become a sequence of unexplained approvals.
Strengths
- Interactive outbound rules and multi-node interface
Best for
- Linux users reviewing application connections
Sources
- Key features (Oct 26, 2026)