Configure Nginx for simple defense against cc attacks

ddos attack: a distributed denial of service (ddos) attack that USES a large number of broilers or fakes IP to launch a large number of server requests and eventually bring down the server.

cc attack: similar to ddos attack, but it is characterized by a large number of page requests, so the traffic is low, but can cause the page to be inaccessible.

Simple defense against cc attacks using Nginx's configuration
===================================================================

Mainly through nginx and lua to cooperate, to achieve the purpose of defense.

1. Nginx compilation supports lua
------------------------------

1. Download lua nginx -- module

wget https://github.com/openresty/lua-nginx-module/archive/master.zip
unzip master.zip

2. Compile

#./configure \
--user=nginx \
--group=nginx \
--prefix=/usr/local/gacp/nginx \
--error-log-path=/data/logs/nginx/error/error.log \
--http-log-path=/data/logs/nginx/access/access.log \
--pid-path=/usr/local/gacp/nginx/conf/nginx.pid \
--lock-path=/var/lock/nginx.lock \
--with-http_flv_module \
--with-http_stub_status_module \
--with-http_ssl_module \
--with-pcre \
--with-http_realip_module \
--with-http_gzip_static_module \
--with-google_perftools_module \
--with-file-aio \
--add-module=../ngx_cache_purge-2.3 \
--add-module=../lua-nginx-module-master

# make && make install

2. The configuration

http {
.....
limit_req_zone $cookie_token zone=session_limit:3m rate=1r/s;
limit_req_zone $binary_remote_addr $uri zone=auth_limit:3m rate=1r/m;


}

server {
listen 80;
server_name localhost;
access_log /data/logs/nginx/access/localhost.access.log main;
error_log /data/logs/nginx/error/localhost.error.log;
charset utf-8;
client_max_body_size 75M;
root /data/www;

location / {

limit_req zone=session_limit burst=5;

rewrite_by_lua '
local random = ngx.var.cookie_random
if(random == nil) then
return ngx.redirect("/auth?url=" .. ngx.var.request_uri)
end

local token = ngx.md5("opencdn" .. ngx.var.remote_addr .. random)
if(ngx.var.cookie_token ~= token) then
return ngx.redirect("/auth?url=" .. ngx.var.request_uri)
end
';
}

location /auth {
limit_req zone=auth_limit burst=1;

if ($arg_url = "") {
return 403;
}

access_by_lua '
local random = math.random(9999)
local token = ngx.md5("opencdn" .. ngx.var.remote_addr .. random)
if(ngx.var.cookie_token ~= token) then
ngx.header["Set-Cookie"] = {"token=" .. token, "random=" .. random}
return ngx.redirect(ngx.var.arg_url)
end
';

}
}

Isn't that easy.