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CCNA 1.9: Configure, verify and troubleshoot IPv4 addressing and subnetting


Subnetting can be a challenge to learn initially.  Instead of trying to write yet another lesson on subnetting I thought I would just include a few good references and create a lab where you can test your skills. I will urge you to watch different YouTube videos on subnetting and read different materials on the topic because it's always good to learn it from different perspectives. Especially on the topic of subnetting.  And practice, practice, practice!  At some point it will click and everything will be clear in the world of subnetting!

Of course, feel free to ask any subnetting questions you might have here.  I'll update the study notes with the best tips and guides.


Study Notes:


PacketTracer Lab: CCNA-1.9-Configure-verify-and-troubleshoot-IPv4-addressing-and-subnetting.pkt

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  1. joseph yang
      May 24, 2019

    i’m trying to understand how you decided the subnets be a and , ….’ ” . 16 , when the CIDR/ is 29 29 and 30. shouldn’t a /29 carry over 5 bits into the 4th octet, which would make the subnet start at (128+ 64+32+16+8 ) ?

    • Joe Barger (CCNP/CCDP)
        May 26, 2019

      As your example shows, /29s have 8 IPs in the subnet and /30s have 4 IPs in the subnet. The /29 subnets therefore begin at .0, .8, .16, .24, .32, .40, .48… all the way up to .248 being the last subnet.
      The subnets in my example work out to the following (network, first available IP – last available IP, broadcast):


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