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| martek 2003-09-18, 11:38 pm |
| Here's a little subnetting puzzle to test your subnetting skills:
Given the IP 10.255.0.255 with subnet mask 255.255.254.0, is the given IP a valid IP or not?
Have fun solving this one.  | |
| justindu 2003-09-18, 11:43 pm |
| i say not valid | |
| darthfeces 2003-09-18, 11:51 pm |
| IP ADDRESS CLASS DEFAULT SUBNET MASK
10.255.0.255 A ff000000 11111111 00000000 00000000 00000000
Applying Subnet Mask: 255.255.254.0 0xfffffe00 11111111 11111111 11111110 00000000
Network Address 10.0.0.0 0xa000000 00001010 00000000 00000000 00000000
Increment 512
Bits Used For Network 15
Possible Subnets 32768
Bits Used For Hosts 9
Hosts Per Subnet 510 | |
| justindu 2003-09-19, 12:10 am |
| Ok i guess it is valid.. LOL | |
| yuvalkoen 2003-09-19, 6:35 am |
| how do you calculate this? what is mean of ff000000 or 0xfffffe00 or 0xa000000? | |
| Demijohn 2003-09-19, 9:20 am |
| He's showing you different ways to write the same thing.
Here are 4 different ways to represent the standard 8 bit class A mask. (Number of bits, dotted decimal, hex and binary)
/8
255.0.0.0
ff000000
11111111 00000000 00000000 00000000
For the mask given in the problem:
/23
255.255.254.0
fffffe00
11111111 11111111 11111110 00000000
You need to be able to look at any of these forms and be able to see (or write out) the other forms without having to think about it. | |
| yuvalkoen 2003-09-19, 11:08 am |
| now i understand. thank you. | |
| bloodshotx 2003-09-19, 12:05 pm |
| You don't need to know hex for the cert. But, its good to know. | |
| darthfeces 2003-09-19, 1:12 pm |
| you only really need to know hex for sniffing
or token ring ? | |
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| of course its a valid IP address. its the last host address of the subnet 10.255.0.0 and 10.255.1.255 will be it's broadcast address. the hex representation is not necessary. | |
| martek 2003-09-19, 10:20 pm |
| The IP is valid, but it's not the last valid IP of subnet 10.255.0.0. The last valid IP is 10.255.1.254 (the broadcast address is 10.255.1.255 and the next subnet ID is 10.255.2.0). |
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