vaild IP address

scout249scout249 Registered Users Posts: 2 ■□□□□□□□□□
Hi All.

I am reading sybex study guide, and a bit confus about IP address

each class A address has 24bit for the node address of a machine. this mean there are 2^24 unique address.

10.0.0.0 is network address
10.255.255.255 is broadcast address.

is 10.0.1.255/8 a valid IP address ? Can i use this address on any device ?


Thanks

Comments

  • wbosherwbosher Member Posts: 422
    Yes, using the class A mask of /8 or 255.0.0.0, you are correct.

    10.0.0.0 is network address
    10.255.255.255 is broadcast address

    The above two address are the only ones you can't use. Anything between these two (including 10.0.1.255) can be used on any device in this network.
  • gothiclonggothiclong Registered Users Posts: 1 ■□□□□□□□□□
    I agree it is a valid IP address.
  • scout249scout249 Registered Users Posts: 2 ■□□□□□□□□□
    Thanks for helping.
  • johnwest43johnwest43 Member Posts: 294
    yup its valid. Now for a quick test.
    Would 10.0.1.255 be a valid host on the networks:

    10.0.0.0/16?
    10.0.0.0/23?
    10.0.1.254/31?

    These types of questions are great practice for studying and for the exams.
    CCNP: ROUTE B][COLOR=#ff0000]x[/COLOR][/B , SWITCH B][COLOR=#ff0000]x[/COLOR][/B, TSHOOT [X ] Completed on 2/18/2014
  • wbosherwbosher Member Posts: 422
    10.0.0.0/16 - Yes
    10.0.0.0/23 - No, broadcast address
    10.0.1.254/31 - No, silly mask that no one would use. There are no valid addresses using this mask.

    Fingers crossed...hope I'm right.
  • networker050184networker050184 Mod Posts: 11,962 Mod
    wbosher wrote: »
    Fingers crossed...hope I'm right.

    Close but no cigar ;)

    http://tools.ietf.org/rfc/rfc3021.txt
    An expert is a man who has made all the mistakes which can be made.
  • wbosherwbosher Member Posts: 422
    Interesting...that little gem about the 31 bit mask wasn't in any CCNA doco that I've read.
  • JaCkNiFeJaCkNiFe Member Posts: 96 ■■□□□□□□□□

    Thanks for this! Great bit of info.
    Lab on!
  • johnwest43johnwest43 Member Posts: 294
    you even get a warning message from the cisco ios when you configure an interface with a /31. try it its neat!!
    CCNP: ROUTE B][COLOR=#ff0000]x[/COLOR][/B , SWITCH B][COLOR=#ff0000]x[/COLOR][/B, TSHOOT [X ] Completed on 2/18/2014
  • sxzaq1sxzaq1 Member Posts: 20 ■□□□□□□□□□
    wbosher wrote: »
    Interesting...that little gem about the 31 bit mask wasn't in any CCNA doco that I've read.

    Watch this video, also, this is video 7 of 9, they are all great for learning subnetting.

    YouTube - Cisco Training CCNA IP Addressing - Part 7

    You'll learn what a rooter is. lol
  • tech-airmantech-airman Member Posts: 953
    scout249,
    scout249 wrote: »
    Hi All.

    I am reading sybex study guide, and a bit confus about IP address

    each class A address has 24bit for the node address of a machine. this mean there are 2^24 unique address.

    10.0.0.0 is network address

    Why is this the network address?
    scout249 wrote: »
    10.255.255.255 is broadcast address.

    Why is this the broadcast address?
    scout249 wrote: »
    is 10.0.1.255/8 a valid IP address ?

    Applying the subnet mask to that IP address, what is the network address?
    scout249 wrote: »
    Can i use this address on any device ?

    Let's wait until you've confirmed that it is a valid IP address.
    scout249 wrote: »

    Thanks
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