Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!VAX.FTP.COM!jbvb
From: jbvb@VAX.FTP.COM (James Van Bokkelen)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: subnet mask problem
Message-ID: <8905301631.AA26360@vax.ftp.com>
Date: 30 May 89 16:31:17 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 18

Long ago, we let users type in the raw, seething subnet mask itself
(255.???.???.???), but they got it wrong a lot of the time, and since
there are many PCs, the effect was large.  We decided to make it
easier on them (and their network administrators), and enhanced the
configuration code to just ask for the number of subnet bits (a much
simpler question to ask/answer), while deriving the actual mask from
the number of bits and the IP address in use.  The underlying IP
module uses the mask itself, not the number of bits.

If anyone *needs* non-contiguous masks, it would take about an hour
for someone equipped with our developer's kit to write a program that
set the mask itself.  If they were a little more patient, we'd do
it for them (might take a release cycle).

Summary: we feel we must weigh flexibility against complexity here.

James B. VanBokkelen		26 Princess St., Wakefield, MA  01880
FTP Software Inc.		voice: (617) 246-0900  fax: (617) 246-0901