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From: Rowland McDonnell on 22 May 2010 09:12 Jim <jim(a)magrathea.plus.com> wrote: > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > > Yes, okay, but what does "192.168/16 block" mean? > > The range of IP addresses from 192.168.0.0 to 192.168.255.255 How might one remember this rather obscure fact? Where does it come from? What is it about "192.168/16 block" which causes it to mean "The range of IP addresses from 192.168.0.0 to 192.168.255.255"? > Each group of 4 numbers is an 8-bit number (0-255), so the /16 means '16 > bits'. Can someone explain what that means? > Hence, 192.168/16 means 'any IP address starting with 192.168' I don't follow. Ta, Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: Richard Tobin on 22 May 2010 09:11 In article <1jiwa2z.gtc68mdoxa4xN%jim(a)magrathea.plus.com>, Jim <jim(a)magrathea.plus.com> wrote: >I'm pretty sure that most routers simply won't route those ranges >anyway. Or at least I'd like to think that they won't. It might be entirely reasonable to route them within a large private network. -- Richard
From: Jim on 22 May 2010 09:18 Richard Tobin <richard(a)cogsci.ed.ac.uk> wrote: > In article <1jiwa2z.gtc68mdoxa4xN%jim(a)magrathea.plus.com>, > Jim <jim(a)magrathea.plus.com> wrote: > > >I'm pretty sure that most routers simply won't route those ranges > >anyway. Or at least I'd like to think that they won't. > > It might be entirely reasonable to route them within a large > private network. Good point. Jim -- "Microsoft admitted its Vista operating system was a 'less good product' in what IT experts have described as the most ambitious understatement since the captain of the Titanic reported some slightly damp tablecloths." http://www.thedailymash.co.uk/
From: Richard Tobin on 22 May 2010 09:20 In article <1jiwc8g.1xumao953fns4N%real-address-in-sig(a)flur.bltigibbet.invalid>, Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: >10.0.0.0 block > >I mean, what's that all about? I don't know what 192.168/16 block >means. 192.168/16 means the subnetwork whose 16 high-order bits are those of 192.168. You might think the "16" is redundant, because 192.168 has 16 bits, but that's just lucky that the number of bits you want to specify happens to be a multiple of 8. You could equally well say 192.168/15, though it's unlikely you'd want to. More plausible would be the case where your ISP gives you a block of 8 addresses, which might be specified as, say, 129.215.197.24/29. 10.0.0.0/8 is the reserved block of 2^24 addresses, 10.x.y.z. It could equally well be written 10/8, and 192.168/16 could be written 192.168.0.0/16. -- Richard
From: Rowland McDonnell on 22 May 2010 09:22
Richard Tobin <richard(a)cogsci.ed.ac.uk> wrote: > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > >10.0.0.0 block > > > >I mean, what's that all about? I don't know what 192.168/16 block > >means. > > 192.168/16 means the subnetwork whose 16 high-order bits are those of > 192.168. Aha! Now that's simple. Thank you. > You might think the "16" is redundant, because 192.168 has > 16 bits, but that's just lucky that the number of bits you want to > specify happens to be a multiple of 8. You could equally well say > 192.168/15, though it's unlikely you'd want to. More plausible > would be the case where your ISP gives you a block of 8 addresses, > which might be specified as, say, 129.215.197.24/29. Ah - righto. Now I understand the use of specifying the number of bits. At least, one use... > 10.0.0.0/8 is the reserved block of 2^24 addresses, 10.x.y.z. Uhuh. > It > could equally well be written 10/8, and 192.168/16 could be written > 192.168.0.0/16. I think I'm getting it now - cheers! Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking |