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Networking

This related to networking in general.

How To Change The TCP/IP MTU On Windows Server 2016

Over the year’s I’ve had numerous occasions arise when I needed to change the MTU on a Windows based computer.  There are a million reasons why this is needed, such as the following.

  • Windows Servers deployed in an OpenStack environment require the MTU to be decreased to 1454 in order to work correctly with Neutron.
  • DSL very commonly uses a smaller 1492 byte MTU when deployed with PPPoE encapsulation, so performance can be significantly degraded if the router and computers are not decreased to match.
  • VPN connections over DSL and some WIFI networks are notorious for failing unless the MTU is adjusted.

 

What Affect Does MTU Have?

 

Packet size, also known as MTU or Maximum Transmission Unit, is the largest amount of data that can be transferred in one packet at the physical layer (OSI Layer 1) of the network. Ethernet’s default MTU is 1500 bytes without using Jumbo Frames.  For PPPoE the MTU is 1492 and dial-up connections typically used 576 back in the day.

Each transmission unit contains of header and actual data. This data is called the MSS, or Maximum Segment Size.  MSS defines the largest segment of TCP data that can be transmitted in a packet.  In a more summarized manner,

MTU=MSS + TCP & IP headers.

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Do You Have a Reliable IP Scanner Installed? Advanced IP Scanner is Quick & Easy.

Every Network Administrator or Security Administrator should have a few basic tools installed and ready to go at a moments notice.  Advanced IP scanner is a reliable and free network scanner.  It offers complete analysis of your entire LAN, showing live IP addresses and giving you the ability to remotely control systems with RDP and Radmin.  It’s installable or fully portable, so you can keep it in your Dropbox or NextCloud folder for convenient access.

 

Key features of Advanced IP Scanner include:

  • Remote Shutdown (and Wake-on-Lan)
  • MAC address to IP resolution
  • Exportable scan results via CSV
  • Quick access to discovered network shares
  • Remote Control via Radmin & RDP
  • Built-in tools such as SSH, tracert, telnet and ping.

 

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Install OpenStack on One Virtual Machine, the Easy Way, On Ubuntu 16.04 LTS!

Many of you have emailed me or posted to voice your gripes about the painful process of installing an OpenStack environment to play around with. I feel your pain! My recent article on deploying OpenStack using conjure-up worked great until a developer committed some defective code.  Some of you even reverted to my old guide on deploying OpenStack on Ubuntu 14.04 from last year.  So, I set out to give you a fool proof, 100% guaranteed deployment method that’s EASY, STABLE, and works on Ubuntu 16.04 Xenial.  Here you go!

Requirements

 

For this guide, you will need a server at least as good as these specs.

  • Virtual Machine on a real hypervisor (ESXi, KVM, Xen, etc) or a bare metal server with virtualization support.
  • 14GB of RAM is the recommended minimum.
  • 100GB of hard disk space, at least.
  • Ubuntu 16.04 LTS server, having already ran sudo apt update && sudo apt upgrade
  • About an hour and a cup of coffee.

 

Installing OpenStack

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Install OpenStack on a Single Ubuntu 16.04.1 Xenial Xerus Server Using Conjure-up

Introduction

 

It’s been some time since I wrote Installing Ubuntu OpenStack on a Single Machine, Instead of 7.  Since then, there have been many updates to both OpenStack, and Ubuntu.

This tutorial will guide you through installing OpenStack on a single Ubuntu 16.04 Server.  I will be installing Ubuntu and OpenStack within a virtual machine hosted on a VMware ESXi Hypervisor, but any fresh installation of Ubuntu 16.04 should work fine, as long as it meets the minimum requirements below.  I will be using conjure-up to install the environment due to the fact that Ubuntu’s Openstack-install package doesn’t working on Ubuntu 16.04.1 at this time.

 

Note:  I have written an updated guide on Installing OpenStack on Ubuntu 16.04 LTS using devstack.  I suggest following that guide unless you have a specific reason for using the conjure-up method.  From my experience, the devstack method requires less resources, runs faster, and performs much better once deployed.

 

Minimum Requirements

 

To install the entire environment on a single physical server or virtual machine, you will need at least:

 

  • 8 CPU’s (vCPUs will work just fine)
  • 12GB of RAM (minimum needed to successfully start everything, more is better)
  • 100GB Disk Space (SSD Prefered, but rotating disk will work)
  • Ubuntu 16.04.1 Xenial Xerus x64 Server(only OpenSSH Server installed)

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Secure Apache In No Time, For Free, With an SSL Certificate From Let’s Encrypt!

Recently, I found out about a non-profit organization called Let’s Encrypt, which came into existence earlier this year.  Let’s Encrypt is a publicly trusted certificate authority that issues FREE SSL certificates.  The SSL Certificates are fully functional and extremely easy to request and install.  In fact, using Let’s Encrypt, it only takes about a minute to request and install an SSL certificate on Apache via the Linux command line, using a few simple commands.  If you have a Linux server(s) running any sort of public facing web server, there is no reason not to do this right now.  Here’s how to do it on Ubuntu 16.04 (although it should be the same process on any version of Ubuntu)!

 

Prerequisites

To install an SSL certificate from Let’s encrypt using this guide, you will need a couple things.

  • A server running Ubuntu 16.04 (although this should work on any version of Ubuntu)
  • Apache installed with a domain name(s) that is resolvable to the IP of the server.
    • If you are hosting multiple domains, you will need to be sure you have Virtual Hosts configured that properly specify the ServerName variable.

 

Install the Let’s Encrypt Client

 

To make things easy, there is a client available, based on python, that will do all of the hard work for you.  The package is called python-letsencrypt-apache.  Let’s use Aptitude to install it.

 

#  sudo apt-get update

# sudo apt-get install python-letsencrypt-apache

 

The client is now installed and we can move on to setting up the SSL certificate.

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Configuring ownCloud 9 & Active Directory / LDAP Plugin Successfully

With this step-by-step guide, you will have your ownCloud 9 (and earlier) cloud server authenticating against Active Directory or LDAP correctly in no time!

Introduction

 

Recently, I went through the process of setting up a brand new ownCloud 9.1 server, after my previous ownCloud server had seen upgrades from 6.x all the way up to 8x.  If you’ve used ownCloud that long, you know the abundant changes and improvements that have been made along the way did not come without their growth pains; especially if you delved into encryption.  So, I decided to start fresh.  I use Active Directory to provide a centralized authentication source for everything in my personal “cloud,” so after setting up my new Dropbox clone, the first thing I needed to do was configure the LDAP user and group backend plugin.  I had a lot of problems getting the Active Directory usernames to match the ownCloud usernames, instead of showing a long string off numbers.  It was a lot of confusing UID, UUID, SAMAccountName and DN related confusion.  There aren’t any great guides to keep you from getting a headache, so I decided to make one.

 

Problems with the LDAP user and group backend plugin

 

It’s pretty straight forward to get an ownCloud server authenticating against and Active Directory server, but the biggest problem I’ve seen is the mapped usernames end up being long strings of numbers in ownCloud.  Although the display names are correct in owncloud, the actual username for all AD mapped logins, by default, are a long unique string makes things difficult.  For one, if you need to get to a users ownCloud data folder, there’s no intuitive way of knowing who’s is who’s folder from the command line.

With this step-by-step guide, you will have your ownCloud server authenticating against Active Directory / LDAP, with the following benefits:

 

  • The ownCloud username will match the Active Directory / LDAP username (no long incomprehensible string of numbers)
  • Any user added to a specified group created in Active Directory will automatically have ownCloud login privileges.
  • ownCloud users will be able to login using their username or email address (if specified in AD) interchangeably.

These three pluses make everything very seemless and saves a lot of headaches. So, lets get started.

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How-To Install ownCloud 9 / 9.1 / 9.x on Ubuntu 16.04 LTS for the ULTIMATE, Private, Dropbox Clone

Introduction

 

Let’s face it, since the advent of Dropbox, Box, Google Drive and the bazillion other cloud-based file synchronization platforms that have came into existence over the past decade, it’s almost a necessity. For the road warrior, using multiple devices, or even the traditional white-collar worker, having access to all of your files no matter what device you’re using is extremely convenient and adds an enormous productivity boost to our lives. One of my biggest concerns with all of the third-party services, however, is privacy and security. Allowing another entity to store my sensitive data, and trusting they will keep in secure, is pretty scary. Thankfully, there are many options to roll-your-own cloud file synchronization and it really doesn’t take much horsepower on the server side. With a low cost VPS (virtual private server), retired computer at home, or even a $25 RaspberryPi, you can easily build your own Dropbox clone that will put you in control of your own data. Today, I’ll walk you through setting up ownCloud 9.1 on Cannocial’s Ubuntu 16.04 LTS. I will be setting up my cloud on a virtual machine running on VMware ESXi, but the process is very similar no matter what hardware platform you choose. This step-by-step guide assumes you have a plain, unmodified, minimum installation of Ubuntu Server 16.04 LTS, with only SSH access. If you don’t have SSH running, or don’t want to enable it, console access will work just fine. So, lets get started!

 

Installing Prerequisites (Apache/MySQL/PHP)

 

Go ahead and login to your freshly installed Ubuntu 16.04 server.  Be sure to login with a username that has sudoer privileges.  This can be the username you selected during installation or specified when you provisioned your VPS.  Let’s make sure everything is up-to-date before going any further. We will use Aptitude to do so.

 

#  sudo apt-get update

#  sudo apt-get upgrade -y

 

Now we can jump in to the nitty gritty.  There are a few standard prerequisites needed for ownCloud to run.  Most people refer to this as the LAMP stack (short for Linux, Apache, MySQL, PHP).

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