Articles which explains the basic concepts of networking
TTL , which stands for Time to Live is a field which is available in the IP header. Take a scenario where a users pings an IP address from his PC. When the IP Packet is constructed for the ping , the TTL value is embedded inside the IP Packet header. Windows based computers...
The article describes the port numbers which is used by telnet protocol. Telnet uses a client server architecture and uses TCP as the transport layer protocol. In the above diagram, a PC and a router is connected to the switch. The IP address of the PC is 192.168.1.2 and that of the router is...
The article describes the process of how a switch learns mac-addresses. In the above diagram, PC1 and PC2 are connected to ports FA0/1 and FA0/2 on the switch. Assume a scenario where the switch has been powered on. After...
The article aims to explains the concept of static routing. In the above diagram, PC1 and PC2 are on two different networks (192.168.1.0 and 192.168.2.0). PC1 and PC2 are connected to the switches, which are connected to the routers. The routers are connected via a point to point link. For PC1 and PC2 to...
Port security is a feature which is available on network switches to block attacks which are based on mac-addresses. Mac-spoofing and cam flooding are two attacks which are based on mac-addresses. In a mac-spoofing attack, an attacker impersonates a valid user, by spoofing the users mac-address. The switch, would then be confused as to...
The article describes two tools which can be used to find the ip addresses which are currently configured on a network. A typical scenario, where this situation is encountered would be a network where a DHCP server is providing dynamic IP addresses to the clients and a File Server needs to be configured with...
A home user has an internet connection at home. The internet is enabled on PC1, through a modem. Internet connection is available only on PC1 and is not shared among any other users at home. There are three users at home. Two users have PC’s (Including PC1 connected to the internet) and another user...
The article explains the fundamental difference between hub and switch. In the diagram above, 3 computers are connected to a hub and a switch respectively. On the hub, let’s assume a scenario where two PC’s are attempting to communicate with each other.Take a scenario where a PC pings another PC. Before transmission, the network...
The article explains the reason as to why there are not ports associated with ping. In the above diagram , there are two PC’s , PC1 and PC2. When PC1 initiates a ping to PC2, the ping packet is constructed on PC1. The source IP address of the IP header carrying the ping packet...
The post explains the concepts of native vlan and how it works in a real time environment. In the above diagram, PC1 is connected to port 2 on the switch SW1. The port is a member of vlan 2. PC2 is connected to port 3 on SW1. The port is a member of vlan...