Packet Sender is an open source utility to allow sending and receiving TCP, UDP, and SSL (encrypted TCP) packets. The mainline branch officially supports Windows, Mac, and Desktop Linux (with Qt). Other places may recompile and redistribute Packet Sender. Packet Sender is free and licensed GPL v2 or later. It can be used for both commercial and personal use.

Features:

• Controlling network-based devices in ways beyond their original apps
• Test automation (using its command line tool and/or hotkeys)
• Testing network APIs (using the built-in TCP, UDP, SSL clients)
• Malware analysis (using the built-in UDP, TCP, SSL servers)
• Troubleshooting secure connections (using SSL ).
• Testing network connectivity/firewalls (by having 2 Packet Senders talk to each other)
• Stress-testing a device (using intense network generator tool)
• Tech support (by sending customers a portable Packet Sender with pre-defined settings and packets)
• Sharing/Saving/Collaboration using the Packet Sender Cloud service.

Note: While the software is classified as free, it is actually donationware. Please consider making a donation to help support development.