When you described flooding for an unknown MAC address, I thought "hey! that's like when a hub is directing traffic on a half duplex network!" and then you confirmed it immediately after. You taught me both things! Thank you so much. :)
@@professormesser You're certainly welcome. My "Thanks!" is for the totality of your tutorial efforts, both here and on your website. Such fantastic resources - keep up the great work!
So a switch is like a piano and when you don't know where traffics going it's like the switch smacks all the keys and hopes it works, and if the switch does know the next note it just presses the right key
for the ethernet frame destination mac address, who's mac address is it exactly if the traffic is going to a different subnet? Is it the Mac address of the default gateway router (the first hop) or is the mac address of the actual device that this traffic is being sent to? If it is the actual recipient's mac then how would a switch know anything about mac address that's on a different subnet or out on the internet even?
@@xFlow777 Yes. There's no way a device will know the MAC address of a device that is in a different network/subnet. This is where routing comes in. So once the frame arrives at the router, the router changes the source MAC address to itself (router's MAC) and then changes the destination MAC address to that of the device based on the ARP table in the router. The router will then forward this frame to the switch, the switch will know what interface the device is connected to based on the destination MAC address. MAC addresses (layer 2 in general) will always be hop-to-hop.
Hey Professor, thanks for putting this up. I am in the middle of a very challenging selection process for an elite bootcamp and am preparing for it with your videos. I also feel well prepared for the Net+ exam, you are a great resource. One interesting question I have about PoE. If the cable itself is originally designed to carry data, isn't sending power over it a much higher load? How much is the difference and wouldn't this need a slightly heavier gauge of wire? Also, wouldn't the current flow cause interference or problems with data flow on the other wires in the cable? Not urgent, thanks for any input you have. Since there is a standard for it, I'm probably worried over nothing and it won't catch fire, but you can understand my concern of course.
A bit of a random question, but could someone cause a DOS by repeatedly contacting a non-existent MAC, forcing the switch to continuously flood the LAN with that traffic?
Yes, this is called LAN flooding. The switch starts broadcasting incoming frames to all ports. This can lead to a significant increase in network traffic, causing congestion, slowdowns, and potentially network outages.The increased traffic and network congestion resulting from the switch flooding the LAN can effectively deny normal network operations, causing a DoS condition for legitimate users. You learn how to secure a network against these types of attacks in Security+.
When you described flooding for an unknown MAC address, I thought "hey! that's like when a hub is directing traffic on a half duplex network!" and then you confirmed it immediately after. You taught me both things! Thank you so much. :)
I just want to jump in to say I really enjoyed the use of the SG1 team - one of my favourite tv shows!
I'm just starting to watch it because of his references. It is good so far.
I hope you checked out SG:Atlantis and SG:Universe after that :D@@cgme9535
Thanks!
Wow! Thanks for the support, and good studies!
@@professormesser You're certainly welcome. My "Thanks!" is for the totality of your tutorial efforts, both here and on your website. Such fantastic resources - keep up the great work!
So a switch is like a piano and when you don't know where traffics going it's like the switch smacks all the keys and hopes it works, and if the switch does know the next note it just presses the right key
That is actually a good way to explain it.
interesting analogy, musician approved 🤣
@@rickraydubsyes indeed. Pianist approved 👋🏻
is it possible to do a reverse ARP, in order to receive an IP address based on a MAC address?
We no longer use RARP for IP addressing, given the nearly ubiquitous use of DHCP.
Awesome Video! Thank you Professor
❤For the SGC!!
Love the stargate reference!
SLAAC uses EUI -64 to create its own address right ?
for the ethernet frame destination mac address, who's mac address is it exactly if the traffic is going to a different subnet? Is it the Mac address of the default gateway router (the first hop) or is the mac address of the actual device that this traffic is being sent to? If it is the actual recipient's mac then how would a switch know anything about mac address that's on a different subnet or out on the internet even?
You’re basically describing the process of “Routing”.
But yes, the destination MAC is going to be that of the router.
@iSgapetti so it's routers Mac address not workstations Mac address that this traffic was intended for?
@@xFlow777 Yes. There's no way a device will know the MAC address of a device that is in a different network/subnet. This is where routing comes in.
So once the frame arrives at the router, the router changes the source MAC address to itself (router's MAC) and then changes the destination MAC address to that of the device based on the ARP table in the router.
The router will then forward this frame to the switch, the switch will know what interface the device is connected to based on the destination MAC address.
MAC addresses (layer 2 in general) will always be hop-to-hop.
Hey Professor, thanks for putting this up. I am in the middle of a very challenging selection process for an elite bootcamp and am preparing for it with your videos. I also feel well prepared for the Net+ exam, you are a great resource. One interesting question I have about PoE. If the cable itself is originally designed to carry data, isn't sending power over it a much higher load? How much is the difference and wouldn't this need a slightly heavier gauge of wire? Also, wouldn't the current flow cause interference or problems with data flow on the other wires in the cable? Not urgent, thanks for any input you have. Since there is a standard for it, I'm probably worried over nothing and it won't catch fire, but you can understand my concern of course.
A bit of a random question, but could someone cause a DOS by repeatedly contacting a non-existent MAC, forcing the switch to continuously flood the LAN with that traffic?
Yes, this is called LAN flooding. The switch starts broadcasting incoming frames to all ports. This can lead to a significant increase in network traffic, causing congestion, slowdowns, and potentially network outages.The increased traffic and network congestion resulting from the switch flooding the LAN can effectively deny normal network operations, causing a DoS condition for legitimate users. You learn how to secure a network against these types of attacks in Security+.
@@DamCrooksta Sweet! Makes me excited to move into Sec+ after this...
You know, I wasted 5 minutes trying to find out what SGC was.