A big thank you to @Chandra Kanth for his question about IPv4 terminology. He sent the question as a private chat, but I want to make sure everyone got to see the reply. My reply is a little bit long to type all here, so I wrote a tutorial and put it on my blog. You can read the entire reply here https://blog.anythingoverip.com/subnetting-vocabulary-decoded-understanding-the-language-of-ip-addressing/ Once you have read the post, jump back here to answer this question. ## Practice Challenge Given: `10.20.30.40/28` - What's the subnet mask in dotted decimal? - What's the network address? - What's the broadcast address? - How many usable host addresses? - Is `10.20.30.60` in the same subnet? Post your answers in the comments - no judgment, we're all learning! P.S - here is a playlist of some videos I made on YouTube MANY MANY years ago, but they are still 100% accurate with IPv4 address - https://www.youtube.com/playlist?list=PLx49hr6omlDuDCBxwMS-wA3AQM7tHUcPa

Scenario: You've been called to troubleshoot connectivity issues at a small office. The network admin configured static NAT for their web server so external clients can access it, but nobody can reach the server from the Internet. Here's what you find: Router(config)# ip nat inside source static 10.0.1.10 203.0.113.50 interface GigabitEthernet0/0 description INSIDE ip address 10.0.1.1 255.255.255.0 interface GigabitEthernet0/1 description OUTSIDE ip address 203.0.113.1 255.255.255.0 The web server (10.0.1.10) can ping the router's inside interface. External clients can ping 203.0.113.1 (the router's outside interface). But nobody can access the web server at 203.0.113.50. ❓ Question: What's wrong with this configuration? Drop your answer below! 👇 Bonus points if you can: Explain WHY it's not working Show the correct configuration 💡 Hint: It's a common mistake that catches a lot of people on the CCNA exam!

Thanks to @Aljon Ruanto for his question related to VLANs. I've created this video to explain VLANs and a little bit more. As always, if there are any questions, please let me know and I'll do my best to respond as quick as I can.