The Internet Assigned Numbers Authority (IANA) has allocated three IP address ranges that are to be exclusively used for private Internet networks: 10.0.0.0 – 10.255.255.255 (10/8 prefix) 172.16.0.0 – 172.31.255.255 (172.16/12 prefix) 192.168.0.0 – 192.168.255.255 (192.168/16 prefix) The first block “10.0.0.0 – 10.255.255.255” is referred to as the 24-bit block, the second “172.16.0.0 – 172.31.255.255” as the 20-bit block, and the third and final block “192.168.0.0 – 192.168.255.255” is referred to as the 16-bit block. 192.168.0.0 – 192.168.255.255 is a set of 256 contiguous Class C network numbers. (IP addresses Read More

A routing protocol is the implementation of a routing algorithm in software or hardware. A routing protocol uses metrics to determine which path to utilize to transmit a packet across an internetwork. The metrics that routing protocols use include: Number of network layer devices along the path (hop count) Bandwidth Delay Load MTU Cost Routing protocols store the results of these metrics in a routing table. A router connects different networks with each other to share packets of data. To route a packet, a router needs to know: Destination IP Read More

A broadcast address is an IP address that targets all systems on a specific subnet instead of single hosts. The broadcast address of any IP address can be calculated by taking the bit compliment of the subnet mask, sometimes referred to as the reverse mask, and then applying it with a bitwise OR calculation to the IP address in question. Some systems that are derived from BSD use zeros-broadcasts instead of ones-broadcasts. This means that when a broadcast address is created, the host area of the IP address is filled Read More

IP Address classes were the original organizational structure for IP addresses. The specific address class would determine the maximum potential size for a computer network. The address class would define which of the specific bits of the address would be used to identify the network and network identification, the bits to identify the host computer and host ID, and total number of host subnets permitted per network. Five total classes of IP addresses were defined, class A through E. Although the IP class term will commonly be used to describe Read More

802.1Q is also known as IEEE 802.1Q or VLAN tagging. It defines a virtual local area network. It is a protocol that allows virtual LANs to communicate with one another using a 3-layered router. It was developed as a part of IEEE 802. Why Was The 802.1Q Standard Developed? Large networks use up a lot of bandwidth and are slow. It is desirable to break up these huge LANs into smaller, more manageable networks. To address this problem, the 802.1Q standard was developed as a part of IEEE 802. This Read More

The Unix/Linux `traceroute` command and the Microsoft Windows `tracert` commands both accomplish the task of tracing network paths, but they do it in slightly different ways. Both of these tools for tracing network routes send out a packet wth TTL (Time To Live) set to 1 and report it's destnation. Then, they send out a packet with TTL=2 and report it's destination. They continue until the packets reach their final destination or the TTL limit is exceeded. The difference is that Unix/Linux `traceroute` uses UDP (User Datagram Protocol) packets to Read More

PCAP (Packet Capture) is a protocol for wireless Internet communication that allows a computer or device to receive incoming radio signals from another device and convert those signals into usable information. It allows a wireless device to convert information into radio signals in order to transfer them to another device. PCAP runs in the background of all wireless devices and plays a critical role in wireless communication, though it is seldom recognized. It has many uses and millions of computer users around the world use it daily. How PCAP Works Read More

An IP (or Internet Protocol) address conflict occurs when two different systems on the same subnet are assigned or otherwise have their network interface configured to use the same IP address. It is possible to have two systems on different subnets configured with the same IP address, but not have a conflict occur due to routing limitations or because of the effects of NAT or Network Address Translation. Systems with the same IP Address on the same subnet need not have the same netmask or broadcast address for the conflict Read More

Cisco is a leading manufacturer of networking devices such as modems, wireless routers, and network storage devices. Cisco products are sold worldwide to millions of consumers for both residential and commercial purposes. Cisco also markets a number of data plans for some of the largest Internet Service Providers in the world. What is 192.168.1.245? 192.168.1.245 is the default IP address of the control panel found on all Cisco routers and devices. Users can access this control panel by entering 192.168.1.245 into any web browser’s address bar. The user will then Read More

Subnetting is the process of breaking down an IP network into smaller sub-networks called “subnets.” Each subnet is a non-physical description (or ID) for a physical sub-network (usually a switched network of host containing a single router in a multi-router network). In many cases, subnets are created to serve as physical or geographical separations similar to those found between rooms, floors, buildings, or cities. There could be more than one definition for subnetting but perhaps the best explanation is that by default a network id has only one broadcast domain. Subnetting is Read More