IP range with prefix - less than /24?

wesley · 27 Oct 2008 at 11:59

hi guys

i understand how to work out how many IP range with prefix /24 and upward but not less than /24 so how to work out?

my understanding that you can add up the 8 (prefix of 24) bits of binary due limited to 255 (broadcast)

thanks

wesley · 27 Oct 2008 at 14:33

thanks guys but how did you work out?

for example : 136.185.86.112/18

IP range would be 136.185.64.1 to 136.185.127.254

but how to work that out?

thanks again

edit: corrected typo!!

wesley · 27 Oct 2008 at 15:17

no i dont want to. i want to learn how to work out so i can do it properly at cisco exam one day

wesley · 27 Oct 2008 at 15:35

ahh i got it now

what about the range stop at 127 in third octet?

wesley · 27 Oct 2008 at 15:40

yes sorry typo

wesley · 27 Oct 2008 at 15:42

always 64's?

wesley · 27 Oct 2008 at 15:49

atomiser said:
vlsm/cidr notation is really straightforward, assuming you actually understand how the dotted decimal notation works?

yes only last 8 bits of binary (4th octet)....../24 to /32

but i dont how to work out under /24 hence this thread

thanks again

wesley · 27 Oct 2008 at 15:54

no........LOL

i'm studying ccna exploration 4 at th moment via online, cisco academy connection site, it doesnt say how do it

wesley · 27 Oct 2008 at 16:06

lol thanks atomiser

so how did u went /18 to 255.255.192.0?

wesley · 27 Oct 2008 at 16:08

alright thanks atomiser, that site is not loading for me at work PC, will check this site when i get home later tonight

wesley · 28 Oct 2008 at 18:40

hi atomiser

i apologise for not getting back to you, i was fitted in the new bath and shower tray last night and should be be finished by tonight.

then will look at it again tomorrow when i'm at work.

that whiteboard site is not working for me

wesley · 8 Dec 2008 at 21:03

hello

just passed CCNA 1 exploration final exam

me very happy

i got few subnet mask questions wrong

thanks guys