Open Source Java Firewall Software

The UPnP PortMapper can be used to easily manage the port mappings/port forwarding of a UPnP enabled internet gateway/router in the local network.

NetGuard is an open-source Android firewall app that lets users control internet access on a per-app basis without requiring root access, making it a straightforward and flexible way to improve privacy and data usage management on mobile devices. By creating a local VPN service on the device, NetGuard intercepts and selectively blocks or allows network traffic for individual applications and addresses, supporting both Wi-Fi and mobile connections according to user preferences. This means you can block internet access for specific apps to save bandwidth, extend battery life, or prevent unwanted background connections while still letting other apps communicate normally. NetGuard’s interface is simple, with toggles to allow or deny access and optional settings for screen-on behavior, roaming, system apps, and notification of internet usage, giving users fine-grained control over network behavior.

A java wrapper for popular "libpcap" and "WinPcap" libraries. Accurate full API translation. Packet buffers delivered with no copies. Send custom packets, gather statistics. Comprehensive and easily extensible DPI engine.

Source: https://github.com/AlizerUncaged/HTTP-Injector respite is a SSH/openVPN client that allows you to connect to the internet with custom injected HTTP Proxy headers. This application requires Java (https://www.java.com/en/download/) and .Net 4.5 (https://www.microsoft.com/en-ph/download/details.aspx?id=42642 .Net 4.5 is already preinstalled in Windows 10). There are many SSH and OpenVPN Server providers in the internet, one is https://www.tcpvpn.com HTTP Proxy responses override (source code): https://github.com/AlizerDoesJava/respite-proxy-override Please rate, any feedback is appreciated. The application and server providers are free.

AFWall+ is a free, open-source Android firewall application that gives users detailed control over network access on rooted devices. Built on Linux iptables, it allows individual applications to be permitted or blocked from accessing the internet. Users can configure separate connection rules for Wi-Fi, mobile data, VPNs, tethering, and local networks. Its profile management system enables different firewall configurations for specific situations. AFWall+ provides connection logging, blocked traffic notifications, and advanced rule scripting for network monitoring. It also supports IPv4 and IPv6, multi-user environments, and automation through Tasker or Locale. By enforcing network restrictions at the system level, it helps reduce unwanted connections, background data consumption, and potential information leaks.

InviZible Pro is a free, open-source Android application designed to improve online privacy, security, and anonymity. It combines Tor, DNSCrypt, and Purple I2P within a single interface for managing encrypted network connections. Tor routes traffic through multiple relays to reduce exposure of a user's identity and location. DNSCrypt encrypts DNS queries and helps protect against DNS surveillance and spoofing. Purple I2P provides access to decentralized anonymous services and I2P websites. The application also offers firewall controls, tracking protection, and configurable network routing. InviZible Pro works on rooted and non-rooted Android devices, with advanced settings for customizing individual privacy modules.

TrackerControl is a free, open-source Android privacy application designed to monitor and restrict hidden data collection by installed apps. It uses Android's local VPN functionality to analyze network connections without requiring root access. The application identifies tracking services and displays the companies and countries associated with outgoing traffic. Users can selectively block trackers, advertising domains, and unwanted network connections. TrackerControl combines multiple tracking databases with static analysis of libraries embedded in Android applications. It also offers DNS-over-HTTPS, custom blocklists, and optional routing through external VPN providers. By processing traffic metadata locally without decrypting HTTPS content, it helps users understand and control mobile tracking.

SonicReader is used to view and save reports of the internals of a Sonicwall Configuration file. This is useful for those people that wish to know the settings within their saved Sonicwall Configs. I have no affiliation with Dell Sonicwall. Please do not contact Dell Sonicwall regarding the use of this program.

iplist is a list based packet handler which uses the netfilter netlink-queue library (kernel 2.6.14 or later). It filters by IP-address and is optimized for thousands of IP-address ranges.

Windows Port Knocking. A Windows implementation of port knocking developed to work alongside an existing firewall (the free CHX-I Packet Filter v3.0).

SOCKS Server and Library for Java. Support for versions 4 and 5 of SOCKS protocol. Designed to be easily expandable to support different encryption/authentication/authorization methods. Sample server and client are available.

Telnet over HTTP proxy. Allows users behind firewalls to tunnel Telnet sessions over a HTTP connection. Server uses Java servlets with a Java or C# client.

VTD-XML is the next generation XML parser/indexer/editor/slicer/assembler/xpath-engine that goes beyond DOM, SAX and PULL in performance, memory usage, and ease of use.

Reduce employee personal Internet usage during the working day. Increase respect of your corporate Internet usage policy, provide open and honest feedback such as WebMail use during work hours. Plugs into an existing proxy or firewall such as Squid.

BadTuxWall will help you to implement your own firewall on a Linux operating system using an efficient graphical user interface. It also allows you to generate iptables scripts, export them and share them with friends.

It moves by itself inside networks like virus infection & plagues, it is being written to solve computer virus problem drastically and responsibly. It is legal, free and open for public domain to improve W3 ICT Security.

CartoReso intends to facilitate enterprise computer network mapping.

The EmailWebBrowser allows users to request and receive web pages through email, even those that would be normally blocked by the user's network.

Server/client suite which provides per-user access control/firewall/QOS. Robust and high speed implementation is secure against MAC/IP spoofing, and can scale to large networks with many clients. Options for additional monitoring and captive portal.

This Library provides a java API for firewall logs, connection tracking and rules management.

IceIDS is heuristic Network Intrusion Detection System (NIDS) based on calculating Student's distributions of network traffic.

InSecT - Invincible Security Technology - an intelligent firewall and intrusion detection system

Infect is a network traffic classification tool, that classifies TCP protocols. The classification is based on ML techniques. Scen: Train/Recognize arbitrary protocols (SSH, HTTPS..), Detect policy violations (e.g. tunnels)

A portsentry clone written in java designed to run on any platform. You be able to give CLI for blocking access after detection (ie. shell, cmd, bat, etc..), Customizable for all ports on UDP,TCP

Jateway is a general purpose TCP/IP connection proxy. Jateway accepts connections on arbitrary ports (like 80 or 443) and specific host:port combinations (like WANIP1:443 and WANIP2:443) for multi-interface systems Supports single TCP connections (like MySQL), and multi-TCP connections like HTTP and HTTPS, and fowards them to arbitrary host/port combinations.