Options

Subnetting

marcj04marcj04 Member Posts: 75 ■■□□□□□□□□
Hey guys,
I've been studying for the Network+ and I was just wondering how important is Subnetting in the real world? Do network admins and engineers find them Subnetting quite often? I find it fun and I want to get really good at it but if it's not even that much of a used skill, then I guess I won't bother. It does seem really useful to me but then again I've never actually worked in a networking environment yet.

Comments

  • Options
    d4nz1gd4nz1g Member Posts: 464
    Every single day.
    I guess it is the most important thing you need to know
  • Options
    joelsfoodjoelsfood Member Posts: 1,027 ■■■■■■□□□□
    VERY useful. To be fair, a lot of engineers/designs just try to use a single /24 per Vlan, etc, but even there, you'll ha ve to break it out as soon as you get a hiring spike, etc. So definitely learn it, don't just cram in the minimum required for the test.
  • Options
    10Linefigure10Linefigure Member Posts: 368 ■■■□□□□□□□
    We use it often, especially in the lab. Learn it and you will be better off at work and later when you study for harder exams.
    CCNP R&S, Security+
    B.S. Geography - Business Minor
    MicroMasters - CyberSecurity
    Professional Certificate - IT Project Management
  • Options
    kohr-ahkohr-ah Member Posts: 1,277
    Always useful. This is how I always remember it below to see ranges at least:

    What is the range per group? Subtract subnet mask from 256.
    ex: 255.255.255.240 so subtract 240 from 256 and it tells you the subnets go in 16s. 192.168.0.0, 192.168.0.16, 192.168.0.32, etc.
    255.255.224.0 so subtract 224 from 256 and it tells you subnets go in 32s. 10.0.0.0, 10.0.32.0, 10.0.64.0, 10.0.96.0, etc.

    Wild cards for ACLs subtract from 255.
    ex: 255.255.255.248 so subtract 248 from 255 and it tells you the ACL would be 0.0.0.7
    255.255.192.0 so subtract 192 from 255 and it would be 0.0.63.255
  • Options
    KragsterKragster Member Posts: 44 ■■□□□□□□□□
    Agree with the others, but will mention that in your environment you'll find yourself using the same masks over and over so you won't even have to do the math anymore eventually. Once you've done it enough it will be just automatic.

    Keep doing the practice stuff and find a method that works for you when you have to do the math on the lesser used subnets. Eventually it will all click and you won't have to do math on the common masks/cidr notations anymore, you'll just know the answer as soon as you see the setup.
  • Options
    fuz1onfuz1on Member Posts: 961 ■■■■□□□□□□
    Net Mask | # of hosts | Bits | Network | Host

    255.255.255.0 | 255^(2^icon_cool.gif hosts | 24 | 192.168.5 | 3

    255.255.0.0 | 255*255^(2^16) hosts | 16 | 192.168 | 5.3

    255.0.0.0 | 255*255*255^(2^24) hosts | 8 | 192 | 168.5.3

    *Increasing hosts, decreasing networks*

    Copied this down into my notes from somewhere on the web.

    kohr-ah - tight!
    timku.com(puter) | ProHacker.Co(nsultant) | ITaaS.Co(nstultant) | ThePenTester.net | @fuz1on
    Transmosis | http://transmosis.com | LinkedIn | https://linkedin.com/in/t1mku
    If evil be spoken of you and it be true, correct yourself, if it be a lie, laugh at it. - Epictetus
    The only real failure in life is not to be true to the best one knows. - Buddha
    If you are not willing to learn, no one can help you. If you are determined to learn, no one can stop you. - Unknown
Sign In or Register to comment.