Nginx实现动态拦截非法访问ip的方法

# Ubuntu/Debian
sudo apt-get install openresty
# CentOS
yum install openresty

sudo apt-get install redis-server  # Debian系
sudo yum install redis             # RedHat系

http {
    lua_package_path "/usr/local/openresty/lualib/?.lua;;";
    lua_shared_dict ip_limit 10m;  # 共享内存区

    server {
        listen 80;
        server_name _;

        location / {
            access_by_lua_file /usr/local/lua/ip_block.lua;  # 核心拦截脚本
            root /var/www/html;
        }
    }
}

local redis = require "resty.redis"
local red = redis:new()

-- Redis连接参数
local redis_host = "127.0.0.1"
local redis_port = 6379
local redis_timeout = 1000  -- 毫秒
local redis_auth = nil       -- 无密码留空

-- 拦截参数
local block_time = 86400     -- 封禁时间（1天）
local time_window = 60       -- 统计窗口（1分钟）
local max_requests = 60     -- 最大请求数

-- 获取客户端IP
local function get_client_ip()
    local headers = ngx.req.get_headers()
    return headers["X-Real-IP"] or headers["x_forwarded_for"] or ngx.var.remote_addr
end

-- 连接Redis
local function connect_redis()
    red:set_timeout(redis_timeout)
    local ok, err = red:connect(redis_host, redis_port)
    if not ok then
        ngx.log(ngx.ERR, "Redis连接失败: ", err)
        return nil
    end
    if redis_auth then
        local ok, err = red:auth(redis_auth)
        if not ok then ngx.log(ngx.ERR, "Redis认证失败: ", err) end
    end
    return ok
end

-- 主逻辑
local client_ip = get_client_ip()
local counter_key = "limit:count:" .. client_ip
local block_key = "limit:block:" .. client_ip

-- 检查是否已封禁
local is_blocked, err = red:get(block_key)
if tonumber(is_blocked) == 1 then
    ngx.exit(ngx.HTTP_FORBIDDEN)  -- 直接返回403
end

-- 统计请求次数
connect_redis()
local current_count = red:incr(counter_key)
if current_count == 1 then
    red:expire(counter_key, time_window)  -- 首次设置过期时间
end

-- 触发封禁条件
if current_count > max_requests then
    red:setex(block_key, block_time, 1)   -- 封禁并设置1天过期
    red:del(counter_key)                  -- 删除计数器
    ngx.exit(ngx.HTTP_FORBIDDEN)
end

-- 释放Redis连接
red:set_keepalive(10000, 100)

ngx.timer.at(0, function()
    local log_msg = string.format("%s - IP %s blocked at %s", 
        ngx.var.host, client_ip, ngx.localtime())
    local log_file = io.open("/var/log/nginx/blocked_ips.log", "a")
    log_file:write(log_msg, "\n")
    log_file:close()
end)

# 模拟高频请求
ab -n 100 -c 10 http://your-domain.com/
# 检查Redis
redis-cli keys "limit:block:*"

redis-cli ttl "limit:block:1.2.3.4"  # 返回剩余秒数

# 采集Redis指标
prometheus-redis-exporter --redis.address=localhost:6379

local rule_key = "limit:rule:" .. ngx.var.uri
local custom_rule = red:hget(rule_key, "max_requests")