Packet Sniffer SDK for Windows   
http://www.microolap.com

Packet Sniffer SDK is a library set for packet capture and network analysis for all Win32 platforms. The main features of the Packet Sniffer SDK library are: Any pre-installed packet drivers are not required; Support of 1GBit networks; Support of all modern development environments for Windows; All PSSDK editions (VCL, DLL, and static libraries) are compiled from the same well-optimized C code. Therefore you may be assured that any Packet Sniffer SDK improvement is implemented in all its editions; Support of multiprocessor (SMP) systems; Support of packet filtering by BPF (BSD Packet Filter, user-settable packet filters) on the internal packet driver level; Supports of new FastBPF technology (Just-In-Time BPF filters compilation, works approximately 6 times faster than "classic" BPF filtering); Support of packet generation and sending functions; Support of local TCP/UDP traffic capturing with binding it to processes (including loopback traffic); Assembling of TCP sessions in data streams; High-performance traffic delivering to application and buffering it using queue mechanism; Support of BPF assembler for BPF filters programming; Support of disassembling BPF filters to BPF assembler source texts; All editions of Packet Sniffer SDK components/libraries contain internal packet driver, which is dynamically loaded/unloaded when the application, using Packet Sniffer SDK, is launched/closed.

Packet Sniffer SDK for Windows (DLL Edition)   
http://www.microolap.com

Packet Sniffer SDK (PSSDK) is the most powerful component suite for network packet capture in Windows OS family environment. The main features of the Packet Sniffer SDK library are: No pre-installed packet drivers are required; Packet Sniffer SDK works fine on Gigabit networks; Packet Sniffer SDK supports all modern development environments for Windows; Packet Sniffer SDK (all its editions: ActiveX, VCL, DLL, and static libraries) is compiled from the same well-optimized C code. Therefore you can be assured that any Packet Sniffer SDK improvement is implemented in all its editions; Packet Sniffer SDK supports multiprocessor (SMP) systems; Packet Sniffer SDK supports packet filtering by BPF (BSD Packet Filter, user-settable packet filters); Packet Sniffer SDK supports packet generating/sending functions. All editions of Packet Sniffer SDK components/libraries contain internal packet driver, which is dynamically loaded/unloaded when the application, using Packet Sniffer SDK, is launched/closed. Currently Packet Sniffer SDK is represented in the following implementations: ActiveX,DLL,VCL, and static libraries for Microsoft VC compatible and Borland compilers. Therefore, Packet Sniffer SDK component/library family allows you to use the full power of almost any of the modern visual or non-visual development environment for creating various network applications working with raw network adapter traffic. Using Packet Sniffer SDK the developer does not need to create special network drivers or to learn internal implementation of the network functionalities in all Windows family operating systems. Main Packet Sniffer SDK elements are developed as objects with properties, methods, and events that make the applications development process simpler and more flexible.

Packet Sniffer SDK for Windows (VCL Edition)   
http://www.microolap.com

Packet Sniffer SDK (PSSDK) VCL component set is the most powerful component suite for network packet capture in Windows OS family environment. The main features of the Packet Sniffer SDK library are: No pre-installed packet drivers are required; Packet Sniffer SDK works fine on Gigabit networks; Packet Sniffer SDK supports all modern development environments for Windows; Packet Sniffer SDK (all its editions: ActiveX, VCL, DLL, and static libraries) is compiled from the same well-optimized C code. Therefore you can be assured that any Packet Sniffer SDK improvement is implemented in all its editions; Packet Sniffer SDK supports multiprocessor (SMP) systems; Packet Sniffer SDK supports packet filtering by BPF (BSD Packet Filter, user-settable packet filters); Packet Sniffer SDK supports packet generating/sending functions. All editions of Packet Sniffer SDK components/libraries contain internal packet driver, which is dynamically loaded/unloaded when the application, using Packet Sniffer SDK, is launched/closed. Currently Packet Sniffer SDK is represented in the following implementations: ActiveX,DLL,VCL, and static libraries for Microsoft VC compatible and Borland compilers. Therefore, Packet Sniffer SDK component/library family allows you to use the full power of almost any of the modern visual or non-visual development environment for creating various network applications working with raw network adapter traffic. Using Packet Sniffer SDK the developer does not need to create special network drivers or to learn internal implementation of the network functionalities in all Windows family operating systems. Main Packet Sniffer SDK elements are developed as objects with properties, methods, and events that make the applications development process simpler and more flexible.

PlasticSniffer   
http://www.plasticwater.com

Simple, small, fast packet sniffer with file logging and address/port filtering. Also includes Conversation window allowing all packets between two addresses to be viewed at once. Can be set to scan and log at startup.