IT guys I need you!

[JordanHill]

I have just passed my comptia A+ 801 & 802 and am now studying windows 7. We are learning about networks and i just cannot get my head around subnets, host and networks etc.. All the formulas just confuse me.

 

Like finding the incrament values then finding subnets then the valid ranges! Its alot to take in for today haha but any help will be great!

 

Cheers guys!

[Grundy]

Hehe, did my Comptia the other year.

 

Subnets are fun

 

You just need to get your head around binary! If you have any test questions etc, drop them through and I'll help you out ( Or try )

Edited November 27, 2013 by grundy225

[r37]

i had to do variable length subnet masks for my CCNA, i still have a headache 5 years later. Once you know whats going on you'll be fine. Its getting your head round it thats the issue.

[JordanHill]

I think im going to go home and watch some professer messer videaos and see if that helps lol, ive got win7 this week then server next week.. Then ccna in around 6 months after working for a bit!

 

I really want to shadow someone at work so i can see what its like to work in an it support role.. All we have done so fare is all in classrooms and really want to see what its like. Im aiming for 1st line support but not sure to what extent i need to know things.

 

Cheers for getting back to me guys!

[DoogyRev]

+1 on the above.

 

Takes a bit of time to get your head round it, it will just click.

 

I cheat and use a subnet calculator . . . but you still need the fundamentals to understand it

[Fodder]

+1 on the above.

 

Takes a bit of time to get your head round it, it will just click.

 

I cheat and use a subnet calculator . . . but you still need the fundamentals to understand it

+1 re understanding fundamentals and then using a calc

Edited November 27, 2013 by Fodder

[Commander]

Subnets are dead easy

 

Take for example, 192.168.1.10 255.255.255.0, the key to working out your network / host / broadcast addresses is the subnet mask, in binary.

 

So, 255.255.255.0, can also be written as "/24", because in binary it's 11111111.11111111.11111111.0, which is twenty-four 1's all in a row, hence /24. Why this is useful is because if you were to write out the IP address and the subnet mask above / below each other, you'd get something like this;

 

192.168.1.10

255.255.255.0

 

Now, everywhere that your subnet mask has a "1" in it (remember to think of it in Binary), then that'll be your Network address. In this example, this means that your network address in this example is 192.168.1.0 - this is because each portion of your IP address is always represented by eight binary digits.

 

Once you've worked that out, your first real address in the range is the next one along, so .1 in this case. To work out the last address in the range we go back to the binary subnet mask... we know there are eight zeros at the end of the subnet mask which represent your addressable range, so what's the biggest number you can make from Binary 11111111? The answer is 255, which is therefore your Broadcast address. Take one away from this and you get your highest usable IP address, 254.

 

This is summed up as

Host IP = 192.168.1.10

Subnet Mask = 255.255.255.0

Network Address = 192.168.1.0

Broadcast Address = 192.168.1.255

Addressable range = 192.168.1.1 - 192.168.1.254

 

Now, if we apply those same principles to something a bit harder, let's say 192.168.22.126 /28 - what do you get?

 

Host IP = 192.168.22.126

Subnet Mask = 255.255.255.240

Network Address = 192.168.22.112

Broadcast Address = 192.168.22.127

Addressable range = 192.168.22.113 - 192.168.22.126

 

 

Knowing all of this stuff is really important, especially when you start doing Routing, ACLs, Firewalls, Network design, etc... But most of my customers just use this http://www.subnet-calculator.com/cidr.php which does the job, but it's no substitute for understanding it yourself.

[Grundy]

I think im going to go home and watch some professer messer videaos and see if that helps lol, ive got win7 this week then server next week.. Then ccna in around 6 months after working for a bit!

 

I really want to shadow someone at work so i can see what its like to work in an it support role.. All we have done so fare is all in classrooms and really want to see what its like. Im aiming for 1st line support but not sure to what extent i need to know things.

 

Cheers for getting back to me guys!

1st Line support, it's all down to what business you work for.

 

- Could work for a specific software company, and you'd be first point of call for the issues with that software

- Could be a general company (I'm in a housing association company) And you get all sorts such as - Need new Equip, No internet access, Error messages appearing, 'Questions - Can I do this, or can I get this', access to Folder, Files, Software etc.

 

It's a hard one to nail, but 1st line can cover a whole lot of things, you just need various IT knowledge and 'the throw your self in the deep end attitude'

[MrLizard]

Worth understanding but although I do quite a lot of networking i always use a calculator, ive had to use the binary method about twice this year..

 

ipv6 is also fun

 

where are you based?

Edited November 28, 2013 by MrLizard

[biggzi]

Subnets are a b****

 

I'm pretty good at maths but it still confused the hell outta me! There are lots of videos on youtube just keep reading and repeating it will stick eventually.

 

But tbh I wouldn't worry about it too much. If you are not in the business of actually setting up new networks you will rarely need to work out subnets. Working 1st line support I'd worry much more about knowing how to "switch it off and back on again"

[MrLizard]

Working 1st line support I'd worry much more about knowing how to "switch it off and back on again"

 

That doesnt change through 2nd and 3rd line