fengjijiao

https://unix.stackexchange.com/questions/125382/migrate-socat-init-script-to-systemd
For socat, I use a pure systemd approach. This is an example for a serial loopback:

[Unit]
Description=Socat Serial Loopback
#Before=my-other.service

[Service]
Type=simple

fengjijiao

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"time"

	"github.com/gin-gonic/gin"

fengjijiao

#!/bin/bash
# this script creates an IPIP Tunnel
# tested for CENTOS 6 & 7

#----------------------------
#        CONFIGURATION 
#----------------------------

# name of tunnel
name='tun_test'   

fengjijiao

package main

import (
	"flag"
	"io"
	"net"
	"time"

	log "github.com/sirupsen/logrus"
	"golang.org/x/net/proxy"

fengjijiao

// Golang example that creates an http client that leverages a SOCKS5 proxy and a DialContext
func NewClientFromEnv() (*http.Client, error) {
	proxyHost := os.Getenv("PROXY_HOST")

	baseDialer := &net.Dialer{
		Timeout:   30 * time.Second,
		KeepAlive: 30 * time.Second,
	}
	var dialContext DialContext

fengjijiao

#!/bin/bash
apt update && apt upgrade -y
apt install strongswan strongswan-pki libcharon-extra-plugins net-tools wget -y
DEBIAN_FRONTEND=noninteractive apt-get -y install iptables-persistent

HOST_NAME="vpn.example.com"
read -e -i "$HOST_NAME" -p "VPN host name: " HOST_NAME
HOST_NAME="${input:-$HOST_NAME}"

LOCAL_SUBNET="172.19.240.0/20"

fengjijiao

// In this file we use a data URL to represent a Blob. This basically base64
// encodes the Blob and puts that string in a URL. This has better compatibility
// with old browsers, but is limited to ~2MB.

const blob = getBlobFromSomewhere()

const reader = new FileReader()
reader.onload = function (event) {
  const a = document.createElement('a')
  a.href = event.target.result

fengjijiao

How to tunnel SSH over SSL/TLS

laptop ssh -> laptop stunnel -> evil network -> internet -> your server -> your server ssh

Server (your shell server/home box/work box/whatever)

Sets up a stunnel process listening externally on port 2443/tcp, forwards to localhost 22/tcp

• Install stunnel, e.g. yum install stunnel
• Install server config snippet to /etc/stunnel/stunnel.conf

fengjijiao

# /etc/sysctl.d/wireguard.conf
net.ipv4.ip_forward=1
net.ipv6.conf.all.forwarding=1
net.ipv6.conf.default.forwarding=1
net.ipv6.conf.eth0.proxy_ndp=1

#/etc/wireguard/wg0.conf   (DO virtual machine)
[Interface]
# The server interface does not actually need an ipv6.
# The 2 following must be repeated for each used addres [0, 1]

fengjijiao

#!/usr/bin/sh

apt-get install -y libglib2.0-0 curl gnupg > /dev/null
cat <<EOF | gpg --import
-----BEGIN PGP PUBLIC KEY BLOCK-----

mQINBGCXz3sBEAC0MuPb6suILUH2uzCFrd6McTPNr+QM8fCK0KQ81ezrRiM/Kzbw
mCK/Dp8oXs85+3hX5bWfSWgnat4Lflsju7WU7c/VnmR4e263/5/dAt00SL0I14Se
skVCOIx3OVaEpjWBZYLTBPf6oE7MY7Y0sQROVeAh+MYJM9E0YE6pDtxNYFWmbVEq
9NjFn4YdgGSlDrHmUv2BiWDfNcuRqAkHCmgWHt4BGI6wfX6UvX2rMkybWOl9OsyA