On Tue, 14 Oct 2008 12:57:07 +1100, "Sarton O'Brien" <[EMAIL PROTECTED]> wrote: > On Tuesday 14 October 2008 06:14:35 Joel Newkirk wrote: >> PS: ipcalc is a handy tool... >> >> $ ipcalc -b 192.168.1.20/29 >> Address: 192.168.1.20 >> Netmask: 255.255.255.248 = 29 >> Wildcard: 0.0.0.7 >> => >> Network: 192.168.1.16/29 >> HostMin: 192.168.1.17 >> HostMax: 192.168.1.22 >> Broadcast: 192.168.1.23 >> Hosts/Net: 6 Class C, Private Internet > > But you'll lose those awfully useful on-demand binary skillz :) > > Seriously though, nice tool. Would have been really handy when I was > bothering > with cisco, if only to give to the people looking over my shoulder ;). I > swear > they sit around trying to figure out how to confuse people as much as > possible. > > Sarton
sort of like riding a bicycle... My first computer I programmed via a hex keypad, 1802 machine code (no assembler, no mnemonics, just hex opcodes), so at the start of things I became (painfully) familiar with hex<->dec<->bin relationships, masks, and binary arithmetic. (I still see things like 'a*8' while my brain thinks 'a<<3') For the people over your shoulder you should omit the '-b' flag, which tells it to skip the bitwise output... ;) $ ipcalc 192.168.1.20/29 Address: 192.168.1.20 11000000.10101000.00000001.00010 100 Netmask: 255.255.255.248 = 29 11111111.11111111.11111111.11111 000 Wildcard: 0.0.0.7 00000000.00000000.00000000.00000 111 => Network: 192.168.1.16/29 11000000.10101000.00000001.00010 000 HostMin: 192.168.1.17 11000000.10101000.00000001.00010 001 HostMax: 192.168.1.22 11000000.10101000.00000001.00010 110 Broadcast: 192.168.1.23 11000000.10101000.00000001.00010 111 Hosts/Net: 6 Class C, Private Internet Seems most people who don't understand binary all the way down to their souls can't even see the dotted quads, their eyes and brains get stuck on the 'big' block of binary. For those interested in achieving understanding of netmasks it can be helpful to generate a few of these for familiar networks and look at the binary portion... The meaning of a /29 netmask for example is pretty clear above. j _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community