Learn about RFC1918, CIDR calculators, and ways to calculate and decide upon the numeric schemes you can design into your network to support the number and types of hosts you expect to connect.
- [Instructor] You will be setting up a network in this course. In the real world, you would do this to support client systems and servers and printers and the like. So the question you need to answer now is how many devices on my network will need an IP address at the same time? That's harder than it sounds because you may not think of it this way now but if you open up a network reporting tool like Netstat, and just look at the report on IPv4 addresses in use on your current subnet, it is probably a lot more than you would think. That's because we have way more devices on a typical network than we think about as administrators. We have phones and tablets and laptops, we have watches too and desktops and servers and printers, but we also have refrigerators now and blood pressure cuffs and dog locator tags and goodness knows what else. When you start keeping track, you quickly realize that you're dealing with numbers that are perhaps three or four times greater than you anticipated. We'll anticipate those numbers and accommodate them or you will find yourself reconfiguring the size and scope of your network later on. Be certain to configure your LAN to use a range of IP addresses that fall within one of the three non internet routable IP address ranges intended for use on private networks as defined IN RFC 1918. The Internet Assigned Numbers Authority IANA has reserved the following three blocks of the IP address space for private internets as shown here. A cidr calculator can help you to properly define your IP address range and subnet mask and there are many on the internet to choose from. For our purposes, we're going to be using a 192.168.0.0/24 network notation, which means our subnet mask will be The resulting range has a maximum possible 254 client addresses on it. This range is common as many routers come pre-configured with a range that is identical. While I recommend using the same range in your test environment for ease of learning, you may use any address range in the ranges of private addresses defined in RFC 1918.
- Designing your network
- Creating firewall schedules and rules
- Setting up a virtual IP
- Using aliases to group hosts
- Preventing local traffic from exiting to the internet
- Using Snort and other intrusion detection systems
- Prioritizing VoIP traffic
- Blocking access to specific websites
- Troubleshooting gaming performance issues
- Interpreting TCP flag definitions