Local Broadcast and Directed Broadcasts - Description and Demonstration

In this video we'll pick apart Broadcasts -- specifically the difference between a Local Broadcast and a Directed Broadcast (which is sometimes referred to as a Targeted Broadcast).
This is the "short version" of this video. In the longer video, we'll run through the same demonstration, but I'll also show you the packet captures of what is so you can see exactly what is happening on the wire.
0:00 - Start
0:11 - Topology
0:21 - Official Definition of a Broadcast message
0:49 - Layer 2 Broadcast vs Layer 3 Broadcast
1:24 - Local Broadcast
2:16 - Demonstration: ping 255.255.255.255
3:14 - Directed Broadcast - speaking to all hosts in the LOCAL subnet
3:54 - Demonstration: pinging the Broadcast IP of a Local Network
4:32 - Directed Broadcast - speaking to all hosts in a FOREIGN subnet
5:23 - Demonstration: pinging the Broadcast IP of a Foreign Network
6:20 - Summary
6:44 - Directed Broadcasts are a Security Risk
The Local Broadcast IP is always 255.255.255.255. Regardless of what your Subnet IP addresses are, you can always use the specially reserved IP address of 255.255.255.255 to send a packet to everyone on the local IP subnet.
The Directed Broadcast (also called Targeted Broadcast) is the last IP address in each Subnet (also known simply as "the broadcast IP"). You can use the Directed Broadcast to speak to every host in your own local Subnet.... OR, you can send a packet to a Broadcast IP in another subnet to speak to every host in a Foreign network.
To calculate your Broadcast IP, you'll have to do a little Subnetting. This video series will teach you everything you need to know about Subnetting:
• Subnetting Mastery
If you are studying for your CCNA, you'll want to check out the compendium of free CCNA study resources from Practical Networking .net:
www.practicalnetworking.net/i...

[@PracticalNetworking]

I'm doing something different with this... I'm releasing 3 versions of this content: An Article, a Short Video, and a Long video. Pick your favorite =). Article www.practicalnetworking.net/stand-alone/local-broadcast-vs-directed-broadcast/ Short Video kzbin.info/www/bejne/kH-7dZWwlqaAY6s Long Video kzbin.info/www/bejne/pKqZfqaJgcdrldE

[@phuongdinh6625]

very clever man!,many thank for your content.I'm currently particular in learning and practise CCNA. Hope for next few months, i can get my first CCNA cert.Thank you!

[@scottspa74]

Long vid. My vote (if that's what this is for)

[@scottspa74]

I just love you, man. Your content is fantastic. The illustrations are always helpful. And, you really seem to get granular, and include concepts that most instructors may ignore, or gloss over. Great stuff,, man. Soooo glad I found your channel while reviewing for the CCNA.

[@PracticalNetworking]

Hi Scott. I've enjoyed seeing your comments on so many of my videos =). Glad you are getting a lot out of this content!

[@abhinavnzl]

Your explanation to every topic is crisp and clear. I appreciate you take time out of your busy schedule and create knowledge content for us.

[@PracticalNetworking]

Thanks Kumar. I appreciate that! =)

[@hasan135]

You are a very good trainer. I love the way you explain.

[@PracticalNetworking]

Thank you, Kamrul. I'm glad you enjoy it =)

[@Abdirahmaann]

Ed you are fantastic your illustrations made easy to understand the concept. thank you greating some where in east Africa Somalia

[@CISSP_workshop]

Thanks ! Explanation is amazing. It cleared my concept

[@PracticalNetworking]

Glad you enjoyed it!

[@hardikpatel5387]

Your videos are fantastic!! Keep making them!!

[@vladislavkaras491]

Thanks for such great explanation!

[@jaelski1217]

You're doing a great job! Love your videos!

[@PracticalNetworking]

Thank you =).

[@cottondai]

I am so glad to find you in youtube. You are the father of the teaching network in the earth planet. A request Could you do a series on DNS, how it works and how to troubleshoot related issues?

[@PracticalNetworking]

DNS is on my list. I don't know when I will get to it, but it would be fun to teach. Glad you enjoy the content, thank you for the kind words =).

[@Aki-zv6lq]

thank you, this type of videos help me a lot

[@Ion3353]

Appreciate the extra effort with the clean PowerPoint - thank you!!!

[@PracticalNetworking]

You're very welcome, Lon. Cheers.

[@arianamiri7821]

loved the concise explanation

[@PracticalNetworking]

Noted =) Thank you for the insight.

[@Tony-xc5sk]

Very cool. Instantly subscribed. Thanks for making this simple. Not sure why the Cisco Network Academy tries to encrypt the information only to make it harder to understands. This seems very basic.

[@mahuubao]

Excellent ... well done ...

[@Jp-yx8od]

Please make videos on various tunnels like IPsec and gre. You make things easy to understand. Thanks.

[@S2eedGH]

Great explanation, thanks a lot

[@PracticalNetworking]

You are welcome!

[@paoloteran3177]

Now I understand. Thank you so much!

[@PracticalNetworking]

You're welcome =)

[@lkdipeolu]

I love this.

[@PracticalNetworking]

[@nsxtogo6044]

Great explanation.

[@PracticalNetworking]

Thank you, Bassem =)

[@tvbuff]

I like how you explain with simulations

[@PracticalNetworking]

Thank you, Saiteja =)

[@nikolaosyiannakou7781]

Thank you!

[@PracticalNetworking]

You're welcome, Nikolaos!

[@shriloo]

Great way of explaining ...Please do more videos

[@PracticalNetworking]

Thanks again. Working on finishing this series as we speak: kzbin.info/www/bejne/mJuQipmXoM-fosU

[@browneyedbabes7863]

Thank you!!

[@PracticalNetworking]

You're very welcome!

[@qyzxger790]

very good explained! :)

[@PracticalNetworking]

Thank you =)

[@anashasan2342]

great video 😍👍

[@PracticalNetworking]

Thank you!

[@ApheliosLover-hr8cd]

tysm

[@petephelp971]

Could you make a DNS record a broadcast address and would it act as an umbrella for all ip addresses?

[@ankitsatyal8512]

😍

[@PracticalNetworking]

=)

[@boardkey9670]

wait but i thought router does not forward broadcast messages

[@PracticalNetworking]

Great point! You are correct, Routers don't forward broadcast messages. But the key is what makes a packet a broadcast packet. The answer is in the longer version of this video where I set up packet captures and we look at the packets in Wireshark to explain *exactly* what is going on. kzbin.info/www/bejne/pKqZfqaJgcdrldE

[@shriram5494]

I tried pinging 255.255.255.255 on my local network but I only got a response from my own machine's IP address. The router and other devices are not responding to this ping but they respond to their respective unicast pings. why may this be happening?

[@PracticalNetworking]

Often pings to broadcast address are disabled for security reasons. More details here: www.practicalnetworking.net/stand-alone/local-broadcast-vs-directed-broadcast/#bc-security