openconnect を Homebrew でインストール

プロジェクトリンク

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• openconnect

プロジェクトの歴史

The official project page says OpenConnect development started after testing Cisco's AnyConnect Linux client exposed practical gaps: smartcard and certificate handling limitations, i386-only Linux support, poor NetworkManager integration, and weak Linux distribution packaging. The project therefore began as a compatibility client but with Unix packaging and desktop integration as first-class concerns.

OpenConnect's changelog shows the project expanding from a Cisco-focused client into a compatibility layer for several enterprise VPN products. Juniper support appeared experimentally in the 7.x era, the `--protocol` option was added in 7.07, and later 8.x releases added GlobalProtect, F5, Fortinet, and Array protocol work alongside Windows, Android, SSO, token, and TPM improvements.

採用の歴史

OpenConnect was adopted by package managers and front ends because it solved a common enterprise access problem without requiring Cisco's proprietary client on every platform. Its documentation links to Linux, BSD, macOS, Windows, and Android paths, and it is packaged by Homebrew, Debian/Ubuntu, Fedora, Arch, openSUSE, Alpine, MacPorts, Scoop, and other systems.

The companion `ocserv` server implements an improved version of the AnyConnect protocol, which made the OpenConnect ecosystem useful for both client compatibility and open deployments. NetworkManager integration and libopenconnect API work made it easier for desktop tools and distribution front ends to use the same underlying client.

使われ方

Users run `openconnect` against a VPN gateway, optionally selecting a protocol with `--protocol`. Authentication is handled through forms, certificates, smartcards, token modes, external browser/SSO flows, or protocol-specific mechanisms; after authentication, the client configures a tunnel and routes traffic through TLS, DTLS, ESP, or protocol-specific transports where supported.

Administrators and package maintainers care about OpenConnect because VPN servers are often controlled by employers or institutions, while clients must be installable and automatable on developer laptops, servers, routers, and CI-like environments. The command-line client plus `libopenconnect` gives both scriptable and GUI front ends a shared implementation.

パッケージ好きにとっての重要性

OpenConnect is significant because it sits at the intersection of cryptography libraries, OS tunnel interfaces, corporate authentication flows, and distro packaging. Formula and package updates can affect TLS behavior, SSO compatibility, token handling, platform tunnel drivers, and interoperability with appliance firmware that changes outside the open-source project.

タイムライン

• 2009: Public histories identify the first OpenConnect release era and its original Cisco AnyConnect replacement role.
• 2015: Version 7.05 added preliminary Juniper SSL VPN support.
• 2016: Version 7.07 added the `--protocol` option, formalizing multi-protocol selection.
• 2022: Version 8.20 added F5, Fortinet, and Array protocol work and broadened Windows/tunnel-driver support.
• 2026: Version 9.20 and 9.21 changelog entries show continuing maintenance for Pulse, GlobalProtect, Cisco TLS 1.3 behavior, token handling, TPM auth, and safety fixes.

Related projects

• OpenConnect is related to Cisco AnyConnect/Secure Client, NetworkManager-openconnect, vpnc-scripts, ocserv, GnuTLS, OpenSSL, Wintun, and the VPN appliances whose protocols it interoperates with.

ソース

• https://formulae.brew.sh/formula/openconnect
• https://ocserv.openconnect-vpn.net/ocserv.8.html
• https://www.infradead.org/openconnect/
• https://www.infradead.org/openconnect/changelog.html
• https://www.infradead.org/openconnect/manual.html