# Install ucspi-tcp with Homebrew, apt, MacPorts, Nix, apk, dnf Tools for building TCP client-server applications. Version 0.88 via Homebrew; verified from local package data. ## Install ```sh sudo av install brew:ucspi-tcp ``` Additional install commands: ### macOS - Homebrew (100%): ```sh brew install ucspi-tcp ``` Evidence: local Homebrew formula metadata - MacPorts (94%): ```sh sudo port install ucspi-tcp ``` Evidence: MacPorts ports tree: net/ucspi-tcp/Portfile from https://api.github.com/repos/macports/macports-ports/git/trees/master?recursive=1 ### Linux - Debian apt (92%): ```sh sudo apt install ucspi-tcp ``` Evidence: Debian stable package indexes: ucspi-tcp from https://deb.debian.org/debian/dists/stable/main/binary-amd64/Packages.xz - Nix (92%): ```sh nix profile install nixpkgs#ucspi-tcp ``` Evidence: nixpkgs package indexes: pkgs/by-name/uc/ucspi-tcp/package.nix from https://api.github.com/repos/NixOS/nixpkgs/git/trees/master?recursive=1 - apk (92%): ```sh sudo apk add date ``` Evidence: Alpine Linux edge package indexes: date from https://dl-cdn.alpinelinux.org/alpine/edge/community/x86_64/APKINDEX.tar.gz - dnf (92%): ```sh sudo dnf install date-devel ``` Evidence: Fedora Rawhide package metadata: date-devel from https://dl.fedoraproject.org/pub/fedora/linux/development/rawhide/Everything/x86_64/os/repodata/e5ca8ce900cd68f5419e1c39ae517343100b306336cbaeb70a3c153121d95094-primary.xml.zst ## Package facts - **Package key:** brew:ucspi-tcp - **Package manager:** Homebrew - **Package manager page:** - **Version:** 0.88 - **Source summary:** Tools for building TCP client-server applications - **Homepage:** - **Upstream docs:** - **License:** LicenseRef-Homebrew-public-domain - **Source archive:** - **Generated:** 2026-07-08T07:18:31+00:00 ## Executables - addcr (cli) - argv0 (cli) - date@ (cli) - delcr (cli) - finger@ (cli) - fixcrio (cli) - http@ (cli) - mconnect (cli) - mconnect-io (cli) - rblsmtpd (cli) - recordio (cli) - tcpcat (cli) - tcpclient (cli) - tcprules (cli) - tcprulescheck (cli) - tcpserver (cli) - who@ (cli) - addcr (alias) - argv0 (alias) - date@ (alias) - delcr (alias) - finger@ (alias) - fixcrio (alias) - http@ (alias) - mconnect (alias) - mconnect-io (alias) - rblsmtpd (alias) - recordio (alias) - tcpcat (alias) - tcpclient (alias) - tcprules (alias) - tcprulescheck (alias) - tcpserver (alias) - who@ (alias) ## Install behavior - Post-install hook: not defined - Bottle: available on arm64_big_sur, arm64_linux, arm64_monterey, arm64_sequoia, arm64_sonoma, arm64_tahoe, arm64_ventura, big_sur, catalina, monterey, sonoma, ventura ## Freshness - Page generated: 2026-07-08 - Package-manager version: 0.88 - Local data: ok - Upstream repository: https://cr.yp.to/ucspi-tcp.html - info: No package-manager update timestamp was available. - info: Release/tag comparison is only available for GitHub repositories. ## Project history and usage ucspi-tcp is Daniel J. Bernstein's Unix Client-Server Program Interface implementation for TCP. It provides small command-line tools such as tcpserver and tcpclient for building TCP services and clients around ordinary Unix programs. ### Project history The UCSPI specification is dated 1996 and defines a command-line interface for client-server communication tools. ucspi-tcp applies that model to TCP, with clients and servers setting descriptors and environment variables before executing an application. The official install page identifies ucspi-tcp 0.88 as the latest published package, and the official tarball has a March 18, 2000 last-modified date. The project is distributed from Bernstein's cr.yp.to site rather than through a public source-control repository. ### Adoption history ucspi-tcp became part of the classic djb software ecosystem, especially alongside daemontools-style service supervision and qmail-era mail setups. The input package metadata shows that, despite its age and tarball distribution model, it remains packaged in Homebrew, Debian, Ubuntu, MacPorts, Nix, and other Unix package collections. ### How it is used Package users most often encounter tcpserver, tcpclient, tcprules, tcprulescheck, recordio, rblsmtpd, and helper tools. The official docs describe tcpserver as a way to accept TCP connections and run another program, while rblsmtpd is documented as an SMTP wrapper that blocks mail from listed sites when used under tcpserver. ### Why package nerds care For package nerds, ucspi-tcp is historically significant because it is a compact Unix networking toolkit from the pre-systemd, pre-framework era. It represents a style where small binaries, environment variables, file-descriptor conventions, and package-manager preservation keep old but sharp infrastructure tools available. ### Timeline - 1996: UCSPI specification copyrighted by D. J. Bernstein. - 2000: ucspi-tcp 0.88 tarball published according to official HTTP metadata. - 2002: rblsmtpd documentation records then-current public RBL source status updates. - Current packaging: source_facts lists Homebrew, Debian, Ubuntu, MacPorts, Nix, and other package-manager entries. ### Related projects - The official rblsmtpd page points to tcpserver and tcprules as companion programs within the suite. - The documentation also points to rbldns from djbdns for running RBL or anti-RBL sources. ### Sources - - - - - source_facts.package-manager ## Security Notes broad file, network, media, or database tool signal. - **Geiger risk:** blue / medium - broad file, network, media, or database tool signal ## Source Database Details - **Source Database:** Homebrew formula API - **Tap:** homebrew/core - **Full Name:** ucspi-tcp - **Version Scheme:** 0 - **Revision:** 0 - **Bottle Stable Root URL:** - **Deprecated:** no - **Disabled:** no - **Keg Only:** no - **URL Keys:** stable ## Other Package-Manager Records - Debian apt - ucspi-tcp - 1:0.88-13: normalized package name match | Debian stable package indexes: ucspi-tcp from https://deb.debian.org/debian/dists/stable/main/binary-amd64/Packages.xz | command-line tools for building TCP client-server applications | http://cr.yp.to/ucspi-tcp - Debian apt - ucspi-tcp-ipv6 - 1:0.88-13: normalized package name match | Debian stable package indexes: ucspi-tcp-ipv6 from https://deb.debian.org/debian/dists/stable/main/binary-amd64/Packages.xz | command-line tools for building TCP client-server applications (IPv6) | http://cr.yp.to/ucspi-tcp - Nix - ucspi-tcp: normalized package name match | nixpkgs package indexes: pkgs/by-name/uc/ucspi-tcp/package.nix from https://api.github.com/repos/NixOS/nixpkgs/git/trees/master?recursive=1 - Ubuntu apt - ucspi-tcp - 1:0.88-8ubuntu1: normalized package name match | Ubuntu 24.04 LTS package indexes: ucspi-tcp from https://archive.ubuntu.com/ubuntu/dists/noble/universe/binary-amd64/Packages.gz | command-line tools for building TCP client-server applications | http://cr.yp.to/ucspi-tcp - Ubuntu apt - ucspi-tcp-ipv6 - 1:0.88-8ubuntu1: normalized package name match | Ubuntu 24.04 LTS package indexes: ucspi-tcp-ipv6 from https://archive.ubuntu.com/ubuntu/dists/noble/universe/binary-amd64/Packages.gz | command-line tools for building TCP client-server applications (IPv6) | http://cr.yp.to/ucspi-tcp - MacPorts - ucspi-tcp: normalized package name match | MacPorts ports tree: net/ucspi-tcp/Portfile from https://api.github.com/repos/macports/macports-ports/git/trees/master?recursive=1 - Debian apt - finger - 0.17-17: installed executable or alias match | Debian stable package indexes: finger from https://deb.debian.org/debian/dists/stable/main/binary-amd64/Packages.xz | user information lookup program | http://ftp.linux.org.uk/pub/linux/Networking/netkit/ - Debian apt - r-cran-date - 1.2.42-1: installed executable or alias match | Debian stable package indexes: r-cran-date from https://deb.debian.org/debian/dists/stable/main/binary-amd64/Packages.xz | GNU R package for date handling | https://cran.r-project.org/package=date - Ubuntu apt - finger - 0.17-17: installed executable or alias match | Ubuntu 24.04 LTS package indexes: finger from https://archive.ubuntu.com/ubuntu/dists/noble/universe/binary-amd64/Packages.gz | user information lookup program | http://ftp.linux.org.uk/pub/linux/Networking/netkit/ - Ubuntu apt - r-cran-date - 1.2.42-1: installed executable or alias match | Ubuntu 24.04 LTS package indexes: r-cran-date from https://archive.ubuntu.com/ubuntu/dists/noble/universe/binary-amd64/Packages.gz | GNU R package for date handling | https://cran.r-project.org/package=date - apk - date - 3.0.4-r0: installed executable or alias match | Alpine Linux edge package indexes: date from https://dl-cdn.alpinelinux.org/alpine/edge/community/x86_64/APKINDEX.tar.gz | Date and time library based on the C++11/14/17 header | https://howardhinnant.github.io/date/date.html - apk - date-dev - 3.0.4-r0: installed executable or alias match | Alpine Linux edge package indexes: date-dev from https://dl-cdn.alpinelinux.org/alpine/edge/community/x86_64/APKINDEX.tar.gz | Date and time library based on the C++11/14/17 header (development files) | https://howardhinnant.github.io/date/date.html - apk - finger - 0.5-r0: installed executable or alias match | Alpine Linux edge package indexes: finger from https://dl-cdn.alpinelinux.org/alpine/edge/testing/x86_64/APKINDEX.tar.gz | Small, simple, and portable finger client and server | https://sr.ht/~bpv/finger/ - apk - finger-doc - 0.5-r0: installed executable or alias match | Alpine Linux edge package indexes: finger-doc from https://dl-cdn.alpinelinux.org/alpine/edge/testing/x86_64/APKINDEX.tar.gz | Small, simple, and portable finger client and server (documentation) | https://sr.ht/~bpv/finger/ - dnf - date-devel - 3.0.4-3.fc44: installed executable or alias match | Fedora Rawhide package metadata: date-devel from https://dl.fedoraproject.org/pub/fedora/linux/development/rawhide/Everything/x86_64/os/repodata/e5ca8ce900cd68f5419e1c39ae517343100b306336cbaeb70a3c153121d95094-primary.xml.zst | Date and time library based on the C++11/14/17 header | https://github.com/HowardHinnant/date - dnf - finger - 0.17-83.fc44: installed executable or alias match | Fedora Rawhide package metadata: finger from https://dl.fedoraproject.org/pub/fedora/linux/development/rawhide/Everything/x86_64/os/repodata/e5ca8ce900cd68f5419e1c39ae517343100b306336cbaeb70a3c153121d95094-primary.xml.zst | The finger client ## Related links - [Secret-risk packages](https://www.automicvault.com/pkg/secret-risk-packages/) - Has protected-tool coverage, approval-gate, or non-low Geiger security signals. - [Terminal utility packages](https://www.automicvault.com/pkg/terminal-utilities/) - Matched terminal and command-line workflow metadata. - [Networking and protocol packages](https://www.automicvault.com/pkg/networking-protocol-tools/) - Matched network, protocol, or remote-service metadata. - [Web development packages](https://www.automicvault.com/pkg/web-dev-tools/) - Matched web development metadata. - [djbdns](https://www.automicvault.com/pkg/brew/djbdns/) - Popular package that depends on this formula. - [tproxy](https://www.automicvault.com/pkg/brew/tproxy/) - Shares av.db curated category or tags: cli, networking, tcp. - [dish](https://www.automicvault.com/pkg/brew/dish/) - Shares av.db curated category or tags: cli, networking, tcp. - [dns2tcp](https://www.automicvault.com/pkg/brew/dns2tcp/) - Shares av.db curated category or tags: cli, networking, tcp. - [netcat](https://www.automicvault.com/pkg/brew/netcat/) - Shares av.db curated category or tags: cli, networking, tcp. - [pwnat](https://www.automicvault.com/pkg/brew/pwnat/) - Shares av.db curated category or tags: cli, client-server, networking. - [redir](https://www.automicvault.com/pkg/brew/redir/) - Shares av.db curated category or tags: cli, networking, tcp. - [rinetd](https://www.automicvault.com/pkg/brew/rinetd/) - Shares av.db curated category or tags: cli, networking, tcp. - [ser2net](https://www.automicvault.com/pkg/brew/ser2net/) - Shares av.db curated category or tags: cli, networking, tcp. - [stuntman](https://www.automicvault.com/pkg/brew/stuntman/) - Local metadata places this package in an adjacent workflow. Shared terms: cli, client, client-server, networking, server. ## Combined YAML source View the package source record on GitHub. [combined/ucspi-tcp.yml](https://github.com/automic-vault/db/blob/main/combined/ucspi-tcp.yml) ## Sources - Nucleus package database - Geiger risk classifier - package-page enrichment - curated package history - package version freshness - av.db category and tag curation - package relationship graph - external package-manager database matches - cross-ecosystem install command graph