Category Archives: Command Line

Cisco IOS Fundamentals

cisco

Cisco’s IOS is a command line driven interface for all their devices. There are some basics for logging into a device. Such as physically connecting to the device console port with a serial port, or a roller over cable. For no i’m going to discuss the basic hierarchy to get into configuring the device. One of the most important commands to learn is the “?” command. At any time if you need to know the command that are available to you you can just type in “?”.

? output for user mode

The next thing you should know is the hierarchy into which you need to progress the get though to be able to configure the device i’ll try to make a simple table below.

Mode chart

To configure a device you must move through the hierarchy into the global mode. user>privilege>global. In the next image I’ll walk though these mode until a reach the interface mode.


user>privilege>global>interface

Thank you for reading. I’ll definitely continue these article later.

Installing Active Directory on a Fresh Windows Server

Command Line

In this article i’ll be walking you through installing a new Active Directory Domain Services feature on a fresh copy of Windows Server 2016. If you’re not familiar with Windows AD DS. To put it simply it is a set of programs run on a server that handles security and access for users on a network of machines. A lot of companies are moving into Azure AD DS which is Microsoft’s cloud based solution. Setting one of those up is very similar i’ll cover that in a future article.

Assuming you’ve met the minimum hardware requirements you can find more about that on Microsoft’s website here. Honestly hardware that you will need will vary largely depending on your production needs in field. The next step will be to give the server a static IP and configure it as the DNS for the network it will be the directory for you can read more about that here. Next you’ll want to have a copy of Windows Server installed.

The first step is to install AD DS onto a windows server instance.
Server Manager will normally run automatically when you log in an admin. The powershell command for running server manager is “servermanager.exe”.

Powershell servermanager.exe

Alternatively you can just use the start menu:

Start>Server Manager

Next you’ll want to add the AD DS feature into the server you can do that from the manage menu in the upper left hand corner or the setup list:

Manage >Add Roles and Features

Next a dialogue will remind you to setup a strong password, static IP, and installed updates. Please due so it is always important to patch systems, but do so only according to your organizations protocols you don’t want to kick a bunch of users off while they are working. You’ll probably get a bunch of service tickets. when you are ready just hit next.

Verify strong password, static IP, and updated windows.

Next the setup wizard will ask if you’d like to role-based installation or remote desktop service installation. For the purposes of this article i’ll just do a locally. I’ll cover remote installation in a future article. So select role based and click next.

Role Based

Next it will ask you to select where the AD DS will reside for now i’ll put it on the same server and click next.

Select Destination Server

Next it will ask you to install role just select Active Directory Domain Services, and click add roles to confirm the different features need for active directory.

Select Active Directory Domain Services
Add feature required for AD DS

Next it will ask you if you’d like to add extra features these are worth reading into later but for now just click next.

Adding more features

Next it will remind you to add fail overs or redundant servers and to add a DNS server if you haven’t and it will advertise Azure and office 360 integration into you installation. Click next when you are ready.

AD DS learn more of just click next

Next is just a confirmation of all the stuff you want added if you ready just click install. When it is done just click the close button

install confirmation window

Next i recommend an restart. If you’re in a production environment remember to follow protocols.

In the next article i’ll cover basic set-up of you AD DS. Thanks for reading.

Network Troubleshooting Part 1

Command Line

Even as enterprise infrastructure is moving towards the cloud, physical terminals, clients, devices ect… need to connect to that cloud. Even with wireless networking those wireless access point still need a wired connection. So this is how i go about checking for network connectivity.

Step 1: Check the Physical Layer. If a machine is not connecting to the network. I always pull it out and look at the link state lights. If i see green or amber flashing or steady. I then know at least the machine is connecting to something on the other end. If i don’t see any lights or red lights then i know the problem is somewhere in the physical layer.

Ethernet Link Lights

Often when i pull out the client box i’ll look for any bad kinks in the Ethernet. It not a common occurrence but is its possible that a really bad kink has cause internal rubbing and cross talk noise or even complete failure of the twisted pairs inside the Ethernet.

Step 2: Check the network device settings. You can read more about network device settings here. There is various ways of doing this if you’re on a windows based device with command line “ipconfig /all” you bring up all the relevant adapters and their current configurations. If you’re on a linux based system “lfconfig” will do the same.

ipconfig output

It is important to check the site’s documentation to see if the gateway is correct or if there is a possible ip address conflict. Also it very important to see if the machine is on the right VLAN. I’ll talk more about VLANs and sub netting in another blog article.

Thank your for reading please keep an eye out for part 2.

Cisco’s IOS Overview

cisco

Cisico’s IOS operating system is very different from Apple’s iOS, and the two should not be confused. Ciciso’s IOS is an operating system design to work on very specific hardware, mainly routers and switches that Cisco sells. Is is a command line only system that runs with very low over head that means cisco’s equipment can be very efficient not worrying about user interfaces and graphical processing. That means the size of the OS is still remarkable small most versions of IOS are around 8 MB to Download and 32 MB to run. One of the requirements to download are registering with Cisco and having a service contract to actually run IOS on your equipment. It is generally not available to the public. While non tier 3 switches don’t need IOS, as their hardware is ASIC based. Tier 3 switches inherit functionality from routers and need knowledge of IOS to configure. One of the most interesting qualities of Cisco IOS and routers is the fact that they’re designed to require little or no user interaction in their service life. This “Bullet-Proof” quality of their products is important to most companies as networks are often the backbone that keeps the company working. All vital networks should have redundancies to deal with any issue that might come up. So who should use Cisco routing and switching gear? really most businesses that rely on their computer for daily business but we’re seeing more and more businesses that require solid networks in their locations like fast food restaurant integrating self serve POS terminal for their customers.

Linux File Structure Part 1

Command Line

I started from a mostly windows background. So i’ve made this chart to help myself and other understand and find certain files. This chart contains the top level file structure that most linux distro use. In windows the main files are usually located in the C: in linux all the your files are located in the root directory or “/” within / are the folder listed below.

In windows all the os files are located inside the “windows” folder created by the OS automatically. Within the windows folder all the data the OS needs is subdivided into its own folder like important Binaries and system binaries will be in the system32 folder. In linux that are at the top level in fact if a normal user access their root they will most likely be in /home/”user”/ folder. This folder is similar to Windows C:/users folder. When your attaching a HDD after boot you will usually need to mount it for its filesystem to show up in the /mnt/ folder. I’ll go into this more in a later article but this chart will help you find files in Linux.

FolderNamePurpose
/bin/Important BinariesVital programs (ls, ping, grep)
/boot/Boot DataKernel files
/dev/Device FileDrivers for hardware
/etc/System ConfigurationFiles for OS
/home/User DirectoriesDirectories for all users
/lib/Important Data LibrariesFiles for use by /bin/ apps
/media/Removable MediaCD, USB, DVD
/mnt/Mounted Mediasda1 , sda2
/opt/Downloaded Appsgoogle/chromium
/sbin/System Binariesessential programs fdisk, ifconfig
/srv/Service DataData for the OS like scripts
/tmp/Temporary FileTemp files that are usually clear every reboot
/usr/User AppsData for applications for users
/proc/Process DataFolder for the OS to process programs that are running

Common Linux Commands Part 1

Command Line

Linux is one of the world most ubiquitous operating systems. While there are many GUI or Graphical User interface Distributions or versions available for linux, command line interface is widely used by business and server deployments. Here are some of the most common commands that will help you start. This is by no means a thorough list but a good start. I will put a more parts as i have time.

Help

-h

-help

The help argument is vital if you are unfamiliar with a command just put it after a command to get a rundown of the command its features. For example if you are unfamiliar with wget you would type

wget -h

This will bring up

Navigation

Linus uses a tree structure to store files similar to windows. I’ll go into more detail later. But navigating this tree structure is vital to using linux.

ls

The LS command is short of list this command bassically “lists” the file in your current directory. The best way to learn is to go into a linux terminal and type “ls -h” this will show all the arguments that will help you use effectively.

cd

cd or change directory is also a vital command to navigate Linux it basically changes the directory that you are in. if you type it in without arguments it move you up a level to in the file tree. If you have permission and run the command multiple time it will bring you to the root directory. If you put the name of a folder after command it will move you into the directory specified, for example if you type “cd home” form the root directory you will move into the home folder where the users files are stored.