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Newsgroups: comp.unix.bsd.freebsd.misc Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.cs.su.oz.au!metro!metro!munnari.OZ.AU!news.ecn.uoknor.edu!feed1.news.erols.com!newsfeed.nacamar.de!news.apfel.de!univ-lyon1.fr!fdn.fr!r2d2.fdn.org!sphynx.fdn.fr!causse From: causse@sphynx.fdn.fr (Philippe Causse) Subject: Re: User PPP X-Newsreader: TIN [version 1.2 PL2] Organization: individual - paris - france Message-ID: <EALotq.1Bw@sphynx.fdn.fr> References: <Pine.BSI.3.95.970519184616.5906A-100000@gold.interlog.com> <86yb97tiis.fsf@bitbox.follo.net> Date: Thu, 22 May 1997 20:56:14 GMT Lines: 49 Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:41479 Eivind Eklund (perhaps@yes.no) wrote: : In article <EAL93r.BH@sphynx.fdn.fr> causse@sphynx.fdn.fr (Philippe Causse) writes: : There are three standard classes, yes. And there are a lot of nets : not matching this, which are made by subdividing a class C net, or : joining several class C nets. Yes, of course I agree ! But if you subdivide your network, you will then have a netmask which has a _greater_ number of bits (see previous posting). From what I understand, having a 22bits netmask means that you subdivided a network of class B (16 bits extended to 22) and not a class C, which is already 24 bits... : > This scheme perfectly fits the constants defined in <netinet/in.h>, so : > I honestly doubt that a netmask could be 22 bits ! I correct myself here: I should have stated "A class C network cannot have a 22bits netmask"... (or it's useless). : I've worked with netmasks from 22 to 29 bits - 8 addresses, 64 : addresses, 256 addresses, 1024 addresses. They exists, and just about : everything support it. A lot of things don't support non-continuous : netmasks, though - FreeBSD included. Agreed as weel, netmasks don't need to be strict A, B or C standards. For example, I use a /32 netmask for my point to point links and I could easily use a /22 as well. But why such a waste ? Just for fun, I tried changing the netmask of my lp0 interface from /32 to /30. It still works (of course) but there's no point in doing that since the interface is not able to broadcast ! Result of netstat -r -Ilp0 Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll lp0 1500 <Link> 0 1 0 1 0 lp0 1500 192.168.3/30 sphynx.plip 0 1 0 1 0 Result of ifconfig lp0 lp0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> metric 1 mtu 1500 inet 192.168.3.1 --> 192.168.3.2 netmask 0xfffffffc BTW, I never heard about non-continuous netmasks... What are they ? TIA. : Eivind. Philippe. -- ------------------------------------------------------------------- P. Causse http://www.fdn.fr/~pcausse 4.4BSD/X11R6/Motif-2.0/C++ mailto:causse@sphynx.fdn.fr (UUCP)