PageKite implements a tunneled reverse proxy which makes it easy to make a service (such as an HTTP or SSH server) on localhost visible to the wider Internet, even behind NAT or restrictive firewalls. A managed front-end relay service is available at https://pagekite.net/, or you can run your own.

Phantomsocks is an Internet censorship circumvention tool based on the desync technique, which was introduced in the 2017 paper Your State is Not Mine: A Closer Look at Evading Stateful Internet Censorship.

Further information on the usage could be found on the Wikibooks page Phantomsocks.

sslh is a network protocol demultiplexer. It acts like a switchboard, accepting connections from clients on one port and forwarding them to different servers based on the contents of the first received data packet. Detection of common protocols like HTTP(S), SSL, SSH, OpenVPN, tinc, and XMPP is already implemented, but any other protocol that matches a regular expression can be added. sslh's name comes from its original application of serving both SSH and HTTPS on port 443, allowing SSH connections from inside corporate firewalls that block port 22.

socat is a relay for bidirectional data transfer between two independent data channels---files, pipes, devices, sockets, etc. It can create "listening" sockets, named pipes, and pseudo terminals.

socat can be used, for instance, as TCP port forwarder, as a shell interface to UNIX sockets, IPv6 relay, for redirecting TCP oriented programs to a serial line, to logically connect serial lines on different computers, or to establish a relatively secure environment (su and chroot) for running client or server shell scripts with network connections.

C library implementation of RaptorQ Forward Error Correction for Librecast. RFC6330 (IETF) describes the RaptorQ proposed standard, which LCRQ more-or-less follows. The primary focus has been on building a fast, simple and dependency-free FEC implementation for use with Librecast, and not on strict standards compliance. The code does, however, fairly closely follow the RFC.

ENet's purpose is to provide a relatively thin, simple and robust network communication layer on top of UDP. The primary feature it provides is optional reliable, in-order delivery of packets. ENet omits certain higher level networking features such as authentication, server discovery, encryption, or other similar tasks that are particularly application specific so that the library remains flexible, portable, and easily embeddable.

Nanomsg is a socket library that provides several common communication patterns. It aims to make the networking layer fast, scalable, and easy to use. Implemented in C, it works on a wide range of operating systems with no further dependencies.

YAZ is a C/C++ library for information retrieval applications using Z39.50, SRU or Solr Web Service protocols for information retrieval. It also offers ZOOM API implementing them.

Net::DNS::Resolver::Mock is a subclass of Net::DNS::Resolver, but returns static data from any provided DNS zone file instead of querying the network. It is intended primarily for use in testing.

FRRouting (FRR) is an IP routing protocol suite which includes protocol daemons for BGP, IS-IS, LDP, OSPF, PIM, and RIP.

knockd is a port-knock daemon. It listens to all traffic on an ethernet or PPP interface, looking for special "knock" sequences of port-hits (UDP/TCP packets sent to a server port). This port need not be open, since knockd listens at the link-layer level.

The THC IPv6 Toolkit provides command-line tools and a library for researching IPv6 implementations and deployments. It requires Linux 2.6 or newer and only works on Ethernet network interfaces.

BIRD is an Internet routing daemon with full support for all the major routing protocols. It allows redistribution between protocols with a powerful route filtering syntax and an easy-to-use configuration interface.

aMule is an eMule-like client for the eD2k and Kademlia peer-to-peer file sharing networks. It includes a graphical user interface (GUI), a daemon allowing you to run a client with no graphical interface, and a Web GUI for remote access. The amulecmd command allows you to control aMule remotely.

This package provides a command-line client (gandi) to buy, manage, and delete Internet resources from Gandi.net such as domain names, virtual machines, and certificates.

Net::DNS::Resolver::Programmable is a programmable DNS resolver for offline emulation of DNS.

OpenRDAP is a command line client for the Registration Data Access Protocol. RDAP is modern a replacement for WHOIS, which provides domain name and IP address registration information in JSON format over HTTP.

NNG project is a rewrite of the scalability protocols library known as libnanomsg, and adds significant new capabilities, while retaining compatibility with the original. It is a lightweight, broker-less library, offering a simple API to solve common recurring messaging problems, such as publish/subscribe, RPC-style request/reply, or service discovery.

Command line interface for testing internet bandwidth using speedtest.net.

Net::CIDR::Lite merges IPv4 or IPv6 CIDR addresses.

The IP class allows a comfortable parsing and handling for most notations in use for IPv4 and IPv6 addresses and networks.

Net::Patricia does IP address lookups quickly in Perl.

mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool. mtr can use several network protocols to detect intermediate routers (or hops) between the local host and a user-specified destination. It then continually measures the response time and packet loss at each hop, and displays the results in real time.

Dante is a SOCKS client and server implementation. It can be installed on a machine with access to an external TCP/IP network and will allow all other machines, without direct access to that network, to be relayed through the machine the Dante server is running on. The external network will never see any machines other than the one Dante is running on.