PCAP Filter vs. libpcap, WinPcap, and Npcap

Introduction

libpcap, WinPcap, and Npcap aren't three competing options. libpcap is the packet capture API most tools are written against; it's native on Linux and macOS, and on Windows it needs a driver underneath it. WinPcap was that driver for years and is now discontinued. Npcap, from the Nmap project, replaced it and is what libpcap-based tools use on Windows today.

So for a Windows application, the real choice isn't between three libraries. It's between building on Npcap or building on a commercial SDK like PCAP Filter that ships its own driver. This article covers what changes when you pick one over the other for something you're shipping, not just running yourself.

What Each One Is

libpcap defines the capture semantics, including the BPF filter syntax most packet-filtering tools still use. It doesn't do anything on Windows by itself.

WinPcap was the original Windows driver libpcap tools used. It hasn't been updated in years and shouldn't be a starting point for anything new.

Npcap is the current, actively maintained Windows driver from the Nmap project. It's the default choice for most open-source and internal tools today.

PCAP Filter is a commercial SDK. Its NetFilter component ships its own driver, so your application doesn't depend on Npcap being installed, licensed, or updated separately.

PCAP Filter vs. Npcap for a Production Application

If you're shipping Npcap inside a commercial product, the free version caps you at five installations and has no silent installer, so any real deployment already means buying Npcap OEM. At that point you're paying for a license either way; the difference is whether the driver, the libraries, and the support come from one vendor or two.

PCAP Filter's Royalty-Free license lets you redistribute the driver and libraries as a runtime component of your application at no additional fee, as long as you ship it unmodified and in compiled form.

When to Use Which

If your product depends on packet capture and you're shipping it commercially, a driver you don't own the licensing or update schedule for is a dependency you're managing indirectly. PCAP Filter removes that: one vendor, one license, one thing to update.

If you're building an internal tool, a research project, or something that doesn't get redistributed, Npcap is a reasonable default and most documentation and examples online assume it.

For the API and a working code sample, see Capturing Network Packets on Windows Without Writing Your Own Driver.