在2.4内核中出现了ip_queue，用于将数据包从内核空间传递到用户空间，其不足之处是只能有一个应用程序接收内核数据。到了2.6.14以后，新增了nfnetlink_queue，理论上可最大可支持65536个应用程序接口，而且可以兼容ip_queue。

不过从内核到用户空间的通道还是只有一个，实际上netfilter对每个协议族也只有一个队列，这里说的65536个子队列的实现就象802.1Q实现VLAN一样是在数据包中设置ID号来区分的，不同ID的包都通过相同的接口传输，只是在两端根据ID号进行了分类处理。

本文详细分析了netlink的实现机制。-Ip_queue, 2.4 kernel packet passed from the kernel space to user space, its deficiencies can have an application to receive the kernel data. New to the 2.6.14 nfnetlink_queue can theoretically support 65 536 Application Programming Interface, and is compatible with the ip_queue. However, the channel from the kernel to user space or only one, in fact, netfilter for each protocol family is only one queue, here said 65 536 sub-queue like 802.1Q, VLAN is the same as set in the packet ID number to distinguish different ID packet through the same interface transmission, but at both ends according to the classification ID number. In this paper a detailed analysis of the netlink implementation mechanism.