FrameSeer for Mac

From LGOSystems:

FrameSeer is a native ("Cocoa") application for capturing, decoding and analyzing network traffic on Mac OS X. FrameSeer is released as a universal binary and currently supports Ethernet, AirPort, PPPoE, PPP and loopback interfaces, and uses the System Configuration Framework to continuously monitor and report on physical network interface state. FrameSeer's multi-document design means that you can capture traffic simultaneously in multiple windows. For example, you can capture on Ethernet and Airport simultaneously, or run multiple captures on the same interface (each with different filters), or grab plaintext traffic from the loopback interface and tunneled traffic from another interface during ssh sessions. Capture filters are supported. Once traffic has been captured, commands like "Select Conversation", "Select by Data-Link Source Address" or "Select by Transport Layer Destination Protocol" make selecting and analyzing traffic subsets a breeze. Traffic subsets can also be copied to the clipboard or exported for use in other applications. FrameSeer includes graphical representations so that you can easily see what your traffic is and where it is going.

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