micktwomey

import socket

if __name__ == "__main__":
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.connect(("localhost", 9000))
    data = "some data"
    sock.sendall(data)
    result = sock.recv(1024)
    print result
    sock.close()

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

obscurerichard

slow

This bash script offers quick shortcuts to simulate slower network connections. It is useful when you need to simulate a wireless network on a Linux network server, especially when you are using a virtual machine guest on your local machine or in the cloud.

slow 3G                   # Slow network on default eth0 down to 3G wireless speeds
slow reset                # Reset connection for default eth0 to normal
slow vsat --latency=500ms # Simulate satellite internet  with a high latency
slow dsl -b 1mbps         # Simulate DSL with a slower speed than the default

slow modem-56k -d eth0 # Simulate a 56k modem on the eth1 device. eth0 is unchanged.

eric-hu

-- Adapted from these sources:
-- http://peterdowns.com/posts/open-iterm-finder-service.html
-- https://gist.github.com/cowboy/905546
-- 
-- Modified to work with files as well, cd-ing to their container folder
on run {input, parameters}
  tell application "Finder"
		set my_file to first item of input
		set filetype to (kind of (info for my_file))
		-- Treats OS X applications as files.  To treat them as folders, integrate this SO answer:

losisli

测试平台：DigitalOcean VPS ubuntu14.04 x64, strongswan5.2.2

运行以下命令请使用root权限

一：安装strongswan

由于ubuntu软件仓库中strongswan版本较低，因此从官网源码编译安装

apt-get install build-essential     #编译环境
aptitude install libgmp10 libgmp3-dev libssl-dev pkg-config libpcsclite-dev libpam0g-dev     #编译所需要的软件

klzgrad

朴素VPN：一个纯内核级静态隧道

由于路由管控系统的建立，实时动态黑洞路由已成为最有效的封锁手段，TCP连接重置和DNS污染成为次要手段，利用漏洞的穿墙方法已不再具有普遍意义。对此应对方法是多样化协议的VPN来抵抗识别。这里介绍一种太简单、有时很朴素的“穷人VPN”。

朴素VPN只需要一次内核配置（Linux内核），即可永久稳定运行，不需要任何用户态守护进程。所有流量转换和加密全部由内核完成，原生性能，开销几乎没有。静态配置，避免动态握手和参数协商产生指纹特征导致被识别。并且支持NAT，移动的内网用户可以使用此方法。支持广泛，基于L2TPv3标准，Linux内核3.2+都有支持，其他操作系统原则上也能支持。但有两个局限：需要root权限；一个隧道只支持一个用户。

朴素VPN利用UDP封装的静态L2TP隧道实现VPN，内核XFRM实现静态IPsec。实际上IP-in-IP隧道即可实现VPN，但是这种协议无法穿越NAT，因此必须利用UDP封装。内核3.18将支持Foo-over-UDP，在UDP里面直接封装IP，与静态的L2TP-over-UDP很类似。

创建一个朴素VPN

pandada8

#!/bin/python3
import requests
import re
import os
import requests
import json

def getIp():
    s = os.popen('ssh root@192.168.1.1 ifconfig').read()
    ip = re.search(r'eth0.2[\w\W]+?(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})', s).groups()[0]

inaz2

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>

void ping(int s, char *message)
{
    char buf[8192];

moneytoo

### No longer needed as of nginx-1.13.6-1.el7_4.ngx.x86_64.rpm from nginx.org
### it was compiled against OpenSSL 1.0.2 from CentoOS 7.4 so it supports ALPN (HTTP2 works)

yum -y groupinstall 'Development Tools'
yum -y install wget openssl-devel libxml2-devel libxslt-devel gd-devel perl-ExtUtils-Embed GeoIP-devel rpmdevtools

OPENSSL="openssl-1.0.2l"
NGINX_VERSION="1.13.5-1"
NJS_VERSION="1.13.5.0.1.13-1"

giovtorres

#!/bin/bash

## **Updates to this file are now at https://github.com/giovtorres/kvm-install-vm.**
## **This updated version has more options and less hardcoded variables.**

# Take one argument from the commandline: VM name
if ! [ $# -eq 1 ]; then
    echo "Usage: $0 <node-name>"
    exit 1
fi