OPENVPN源代码，功能强大，在数据链路层做的

一个防火墙的源码，比较适合学习包过滤-a firewall source code, the more appropriate learning packet filtering

华为防火墙培训教程，内容丰富，是学习网络知识的好材料。-Huawei training tutorial firewall, content-rich, knowledge networks are good study material.

微软的一个ndis驱动程序例子,写防火墙的朋友可以参考-A ndis driver example of Microsoft. and it can be referred to those who writes the firewall

好象是windows的防火墙源代码，我不喜欢ms的东东，所以没有研究他的东西，那位有兴趣的看一看!-appears to be windows firewall source code, I do not like ms Dongdong, so he did not study things, who are interested in a look!

网络过滤工具，能自己添加需要限制的内容。-Internet filtering tools that can add the need to limit their own content.

远程安全连接的例子，类似于隧道连接技术，网络安全编程基础-connecting example, similar to the tunnel linking technology, network security based programming

Windows Firewall Ports & Applications Manager -Windows Firewall Ports & Applications Manager

IpFilterHook技术的源代码。包括了2个完整的例子。-IpFilterHook the source code. Including the two complete example.

费尔个人防火墙 2.0 源程序 重要文件/目录说明 Xfilter.dsw - VC 工作区文件，包括以下工程 - TcpIpDogTcpIpDog.dsp - xfilterxfilter.dsp - xpacket2k.dsp ( 限于 2000 版 ) - xpacket9x.dsp ( 限于 95/98/ME 版 ) Common - 存放公用代码文件 RELEASE - 存放编译后的程序 TcpIpDog - XFILTER.DLL 的代码 XFILTER - XFILTER.EXE 的代码 xpacket2k - XPACKET.SYS 的代码 (2000 版才会有此目录) xpacket9x - XPACKET.VXD 的代码 (95/98/ME 版才会有此目录)-Personal Firewall 2.0 Fernando important source file/directory Description Xfilter.dsw-VC work area documents, include the following works- TcpIpDog TcpIpDog.dsp- xfilter xfi lter.dsp- xpacket2k.dsp (limited to the 2000 version)- xpacket9 x.dsp (limited to 95/98/ME version) Common-code document storage utility RELEASE- compiled stored procedures TcpIpDog- XFILTER.DLL code XFILTER- XFILTER.EXE code xpacket2k- XPACKET.SYS code (2 000 version will be in this directory) xpacket9x- XPACKET.VXD code (95/9 8/ME version of this directory will be)

防火墙提供了内核模式的防火墙和 NAT 机制，这些机制可以通过用户模式运行的接口程序进行监视和控制。 防火墙规则可以使用 ipf(8) 工具来动态地设置和删除。 NAT 规则可以通过 ipnat(1) 工具来维护。 ipfstat(8) 工具则可以用来显示 IPFILTER 内核部分的统计数据。 最后， 使用 ipmon(8) 程序可以把 IPFILTER 的动作记录到系统日志文件中。 -Firewall provides a kernel-mode firewall and NAT mechanisms, these mechanisms can be run through the user-mode interface program to conduct surveillance and control. Firewall rules can use the ipf (8) tools to dynamically set up and delete. NAT rules can be adopted ipnat (1) tools to maintain. ipfstat (8) tools can be used to show the core part of IPFILTER statistics. Finally, the use of ipmon (8) program can record the movements IPFILTER to the system log file.