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Introducing To SVI While our L2 switches don’t perform routing (they just switch and that’s all they do), we still need an IP address (a L3 address) on that switch in order to remotely connect to said switch.( we want to configure it without actually having to go to the switch , connect to the […]
Introduction to Routing We’ll start our walkthrough with a basic network and follow the decision-making process from the point of view of the host, then router. We’ll start with this iconfig output from our host PC. When a host sends a packet, there are two possibilities regarding the destination host. It’s on the same subnet […]
When one host sends data to another, that data has both a MAC destination address and an IP address and an IP destination ( Layer 2 destination and Layer 3 destination). Up to this point we’ve been working with L2 destination addresses as opposed to L3 destination. We’re now going to move up a layer […]
The Enemies Within It’s easy to think about network security in terms of playing defense from attackers outside our network. Thing is, plenty of successful attacks have been launched from inside a network, utilizing seemingly innocent network services and protocols such as DHCP, ARP, CDP, Telnet, and even VLANs. Port Security A basic Cisco security […]
Switch and Router Memory : The memory sections and functions discussed in this section are the same for switches and routers, but to avoid saying “switches and routers” 300 time, we’ll just say “switches”. Of the following, take note of which ones lose their contents on a reload and which do not. ROM : Read-Only […]
Trunking Switches ( And the VLANs that love them ) Trunking is the process of creating a logical connection between two physically connected switches, allowing frames to flow between them. As you see, Switch 1 and 2 are connected with a cable (crossover cable) A tag indicating the destination VLAN is placed into the frame […]
Naming a VLAN With “show vlan brief” , we’ll see all VLANs that we created earlier, plus VLAN32 which I just left empty. So we have a couple of empty VLANs here. We have ports 2 and 4 in VLAN24. We can give names to VLANs specially when we have lots of them because it […]
Why Do We Use VLAN? Because they help us group hosts by department, security clearances, or any category, rather than being limited to geographic location. Because they are kind of a security feature and help you increase security by hiding a logical group of host away from everyone else and we can do that wit […]
