Re: etherconf or ifupdown problem with subnets
On Tue, Jul 16, 2002 at 11:31:03AM +0100, Scott James Remnant wrote:
The old classful network defaults are probably still the most sensible.
Absolutely not. I don't know of anyone who actually uses a "class A"
range as a single broadcast network with 16M machines.
If you're arguing that the introduction of CIDR means that we should use
smaller defaults than the old ranges, then a /30 should be the default.
I can't see any argument for any other default range, /24 is far too big
for any real networks to be "useful".
Curious. I'm surrounded by /24's here.
But whatever. The point you seem to missing is that given an address and
netmask, a sane broadcast address can be calculated in most cases.
(Assuming 1's broadcast.) The default will fail in corner cases, but
will usually make sense.
The trouble with the kernel defaults is that given, e.g.,
ifconfig eth0 18.104.22.168 netmask 255.255.255.224
you'll get a broadcast of 22.214.171.124, which is completely silly.
The sensible broadcast default would be 126.96.36.199, which is fairly
easily calculated. Of course there are networks that might use different
broadcast addresses (for whatever silly legacy reason), which is why
it's a default rather than a mandate.
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