Nginx FastOpen 折腾记录


TCP Fast Open

From Wikipedia, the free encyclopedia In computer
networking, TCP Fast Open (TFO) is an extension to speed up the
opening of successive Transmission Control Protocol (TCP) connections
between two endpoints. It works by using a TFO cookie (a TCP option),
which is a cryptographic cookie stored on the client side and set upon
the initial connection with the server. When the client later
reconnects, it sends the initial SYN packet along with the TFO cookie
data to authenticate itself. If successful, the server may start
sending data to the client even before the reception of the final ACK
packet of the three-way handshake, skipping that way a round-trip
delay and lowering the latency in the start of data transmission.

The cookie is generated by applying a block cipher keyed on a key held
secret by the server to the client's IP address, generating an
authentication tag that is difficult for third parties to spoof, even
if they can forge a source IP address or make two-way connections to
the same server from other IP addresses. Although it uses
cryptographic techniques to generate the cookie, TFO is not intended
to provide more security than the three-way handshake it replaces, and
does not give any form of cryptographic protection to the resulting
TCP connection, or provide identity assurance about either endpoint.
It also is not intended to be resistant to man-in-the-middle attacks.

The TFO proposal was originally presented in 2011 and was, as of
February 2012, an IETF Internet Draft. The specification was published
as RFC 7413 in December 2014. TCP Fast Open shares the goal of
bypassing the three-way handshake of TCP with an earlier proposal from
1994, called T/TCP (RFC 1644). In contrast to TCP Fast Open, T/TCP
paid no attention to security, opening a path for vulnerabilities and
failing to gain traction.

TFO implementations include the following:

IPv4 support for TFO was merged into the Linux kernel mainline in
kernel versions 3.6 (support for clients) and 3.7 (support for
servers), and was turned on by default in kernel version 3.13. TFO
support for IPv6 servers was merged in kernel version 3.16. Google
Chrome and Chromium browsers have support for TFO on Linux, including
Chrome OS and Android. As of 2015, Apple Inc. has announced that iOS 9
and OS X 10.11, its next operating system versions, will both support
TCP Fast Open, but it will not be enabled for individual connections
by default. Microsoft Edge supports TCP Fast Open since Windows 10
Preview build 14352.

简单来说就是TCP Fast Open是对tcp的一个增强,用于支持在3次握手的时候也用来交换数据。

目前Windows平台下Chrome暂时还不支持Fast Open (如图)
据说Win10的Edge浏览器支持Fast Open,不过试了一下也感觉不到多大变化【估计IE内核的蜗牛速度把TFO优化的时间都耗没了

因为CentOS 6.7的内核是2.6,TFO至少需要3.7内核,所以折腾前要升级kernel【怎么升级就不说了,网上一搜一大堆】
编辑/etc/sysctl.conf加入net.ipv4.tcp_fastopen = 3,保存后执行sysctl -p
之后在 nginx.conf 的 listen 项后面加上fastopen=3
保存后执行nginx -s reload

server {
    listen  80 fastopen=3;
    charset utf-8;
    set $root_name "/etc/nginx/html";
    if ($host ~* ""){set $root_name "█████████████████";}
    if ($host ~* ""){set $root_name "█████████████";}
    if ($host ~* ""){set $root_name "████████████";}
    root $root_name;
    location / {
        index  index.php;
        if (!-e $request_filename) {
          rewrite (.*) /index.php last;
    location ~ \.php$ {
        if (!-e $request_filename) {
          rewrite (.*) /index.php break;
        include fastcgi.conf;


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