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### 1: Drop invalid packets ###
/sbin/iptables -t mangle -A PREROUTING -m conntrack --ctstate INVALID -j DROP

### 2: Drop TCP packets that are new and are not SYN ###
/sbin/iptables -t mangle -A PREROUTING -p tcp ! --syn -m conntrack --ctstate NEW -j DROP

### 3: Drop SYN packets with suspicious MSS value ###
/sbin/iptables -t mangle -A PREROUTING -p tcp -m conntrack --ctstate NEW -m tcpmss ! --mss 536:65535 -j DROP

### 4: Block packets with bogus TCP flags ###

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Installation OpenStack Xena on VM Cloud

Environment

1. Virtual Machine Ubuntu 20.04LTS (Azure, GCP, AWS, Aliyun, etc)
2. 16GB RAM
3. 512 GB Storage
4. One disk add for PV

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Create Instances for Prometheus Server and Grafana

Download Prometheus Server

cd /tmp
wget -c https://github.com/prometheus/prometheus/releases/download/v2.13.1/prometheus-2.13.1.linux-amd64.tar.gz

Extract Prometheus Server

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## Graphite Setup for CentOS

#### 参考

 * [Install graphite on a CentOS/RHEL server](http://www.linuxsysadmintutorials.com/install-graphite-on-a-centosrhel-server/)
 * [CentOSにRPMでGraphite+Diamondをインストールする](http://qiita.com/takakiku/items/4dbee4739801cb8f60a2)

***
#### epel リポジトリの追加

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• create a new redis .conf file

$ cp /etc/redis.conf /etc/redis-xxx.conf

• edit /etc/redis-xxx.conf, illustrated as below

...

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#!/bin/sh
 
# Script to compile nginx on ubuntu with lua support.
 
NGX_VERSION='1.6.2'
LUAJIT_VERSION='2.0.3'
LUAJIT_MAJOR_VERSION='2.0'
NGX_DEVEL_KIT_VERSION='0.2.19'
LUA_NGINX_MODULE_VERSION='0.9.15'
 

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<?php
  header("Cache-Control: no-cache, must-revalidate"); //HTTP 1.1

  $domains = array('devguppie.com', 'wwww.devguppie.com', 'www.example.com', 'example.com');
  foreach ($domains as $domain) {
      $curl   = curl_init("http://$domain/.*");
      curl_setopt($curl, CURLOPT_CUSTOMREQUEST, "PURGE");
      curl_exec($curl);
      curl_close($curl);
  }

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#!/usr/bin/env python
from __future__ import print_function
import os
import sys
from collections import namedtuple
CacheFile = namedtuple('CacheFile', ['path', 'key'])
def read_cache_file(path):
    with open(path, 'r') as f:
        f.seek(0x28)    # skip header
        key_magic = f.read(6)

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Stop Hotlinking: don’t let other websites steal your content (images, media files, etc),
that will cause additional load to your webserver and also more bandwidth consumption.

'''
location ~ .(gif|png|jpe?g)$ {
     valid_referers none blocked mywebsite.com *.mywebsite.com;
     if ($invalid_referer) {
        return   403;
    }
}

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-- Tit Petric, Monotek d.o.o., Thu 27 Oct 2016 10:43:38 AM CEST
--
-- Delete nginx cached assets with a PURGE request against an endpoint
--

local md5 = require 'md5'

function file_exists(name)
        local f = io.open(name, "r")
        if f~=nil then io.close(f) return true else return false end