Week 2 Blog

Week 2 Course Blog

Introduction

This week was all about network security. This blog will be split into six parts that focus on important parts of this week’s lesson. Security measures are done with both hardware and software and even as far as secured rooms using finger scanners. These security measures differ with ever network.

Application security and software updates

Not every application is perfect, in fact most aren’t. My antivirus software has many updates a week. This is because there’s always new ways for people to get in where they shouldn’t. Linux is great because you can update all installed software with one line of code (su -c 'dnf update').  If you’re logged in as an administrator, then simply type sudo dnf update. If you’re scared that you’ll forget to constantly check for updates, then login as admin and enter sudo /sbin/chkconfig --level 345 dnf on; /sbin/service dnf start. This script automatically updates all software at 4:00 AM.

Network protection and firewalls

There’s safety in numbers for when it comes to networks.  Filtering traffic is a great way to see who’s doing what on a network. A great way to do this is by using a firewall with hardware, software, or both. Firewalls can set rules for an individual IP address and Ports like we did in this week’s lab! We also blocked traffic with just a few commands.

Local Software Firewalls

Most ISPs will provide a physical firewall when setting up a network. This isn’t enough for a larger network. Software firewalls are great for running on a server. This week we used iptables. I mentioned above that you can block incoming and outcoming traffic. Software firewalls can also show if a file server has been compromised. If your file server is making web page requests that’s not a good sign.

Routers and Network Address Translation (NAT)

Every device on a network has their own address, this is so traffic knows where to go. Routers is responsible for mapping your private IP address and port to the web page you’re visiting (like this blog). NAT makes internal private addresses into external public addresses (or external public addresses into internal private addresses) with a router or gateway.

Proxy Servers

Proxy servers are a type of firewall that filters traffic and hide the identity of workstations. The type of traffic that proxy servers filter can be domain names and keywords. Proxy servers also cache data. Here’s an example of caching: open a website you’ve never visited before then close your browser. When you go back to that website, you’ll notice that it loaded faster.

Name Resolution

Name resolution is an easy to understand concept. We use domain names like Google.com because it’s easier to remember than a public IP. On top of that, IPs can change but you can keep the domain name. The domain name has to be translated to the public address so that you’re transferred to the website.

Outro

Hopefully if you’re reading this you’re not learning anything new. If you do, great! If not, review is always important.