Hello everyone welcome to the show "Ethical Hacking" episode 82 today we are going to discuss about Securing network media.Network media is the cabling that makes up our network.This can be copper,fiber optic, or coaxial.And they're going to be used as a connectivity method inside of our wired networks.Now, in addition to all the cables there's other parts of the cabling plant we have to think about.All those intermediate devices like patch panels, punch-down blocks,and network jacks all make up this cabling plant that runs throughout our organization.And each part of that can be a vulnerability for us.The first vulnerability I want to discuss is EMI.This stands for electromagnetic interference.Electromagnetic interference is a disturbance that can affect electrical circuits,devices, and cables due to radiation or electromagnetic conduction that occurs.Now, EMI is something that happens normally inside our businesses and inside our homes.EMI is caused by all sorts of things, like televisions,microwaves, cordless phones, baby monitors,motors like inside your vacuum, and other devices.Anything that is really a powered device,even handheld drills can cause electromagnetic interference.Now, to minimize EMI you need to install shielding around the source, for instance,your air conditioner lets off a lot of EMI.You could put shielding around that.Or you can shield the cable itself by choosing shielded twisted-pair.Now, STP cables, or shielded twisted-pair,have foil around either each twisted-pair in the cable or around the entire bundle of twisted-pairs to prevent emanations out of the cable or interference entering into the cable.STP gives you double benefit, it keeps things out, and it keeps things in.This is good for security and helps minimize this vulnerability.Now, the next vulnerability we have is called radio frequency interference, or RFI.RFI is just another type of interference like EMI.Like EMI it's a disturbance that can affect your electrical circuits,your devices, and your cables.But instead of being caused by electrical waves it's caused by radio waves.Most often from AM and FM transmission towers or cellular phone towers.Now, cell towers and radio towers near your office can be a big source of RFI in your wireless networks.And when you have a significant amount of RFI this can cause to network connectivity problems for your wired networks, as well as disturbing your wireless networks too.Now, this is something that you're going to have to address.And a lot of it is going to be addressed by shielding the building or getting stronger devices that can overcome the radio frequency interference that's occurring.Another vulnerability we have is what's known as crosstalk.Crosstalk occurs when a signal is transmitted on one copper wire, and it creates an undesired effect on another copper wire.So, when we think about having two copper wires,like inside of a twisted-pair cable,if the shielding inside that protects those wires comes off,then we can actually have crossover from one wire to another.And that causes interference because of the data emanations and EMI.Crosstalk is essentially that,but in very close proximity.Now, this becomes very common with older cable network types, things like Cat3 networks,or even some early Cat5 networks.Most of our Cat5E and Cat6A networks aren't really subject to crosstalk nearly as much.Another place is see crosstalk happen a lot is if you have punch-down blocks,and you decide to use an older terminal,like the old 66 blocks that were used for phone lines,and tried to use that for networks.Networks should always use a 110 block,like you learned back in Network because it gives more spacing and prevents crosstalk from occurring.The next thing you want to talk about here is STP cables because STP cables are really helpful to our networks.They can prevent some of that RFI, they can prevent EMI.And they can help with crosstalk.
