Thick Ethernet/Sun networking problems

From: Pete Turnbull <pete_at_dunnington.u-net.com>
Date: Fri Nov 2 16:20:40 2001

On Nov 2, 16:30, Douglas Quebbeman wrote:
> > On Nov 2, 8:03, Douglas Quebbeman wrote:

> Someone else pointed out IFCONFIG; sorry, not a *nix guru.
> I tolerate *nix as Multics' poor deformed little brother.

;-)

> > Don't forget to restore the original address with "ifconfig le0
111.0.0.1
> > broadcast 111.255.255.255 netmask 255.0.0.0 up" when you've finished
:-)
>
> What does 'broadcast' do (other than the obvious)?

It's just a way of explicitly stating what the broadcast address for that
interface is. In every legitimate case I can think of, it should be
redundant if you provide the netmask (or the netmask is redundant if you
give the broadcast address). I'm not sure what happens if they don't
match. Maybe that's allowed if you have multiple IP addresses (ip aliases)
for the same physical interface, then perhaps you could use a "broader"
broadcast address to listen to more than one subnet on the same interface.
 I don't know.

> > It'll take a while to work through the class C range

> Yes, I'd say he would benefit from some filtering if he
> has to check all the class C range, but I was assuming
> this could take a couple of months, worst-case...

You were about right then, I think! I wasn't having a dig at you! Merely
"thinking out loud" and pointing out (in case Arno, for example, didn't see
the implications) that there are rather a lot of addresses :-)

Even then, it might not work. The range of network addresses from
224.0.0.0 to 239.255.255.255 are used for multicast, and no ordinary IP
software uses those for unicast (normal) or broadcast traffic. Above that,
I don;t know of any allocated uses, and things aren't suposed to respond to
them at all, which would be a problem if the setting are corrupt in such a
way as to fall in that range.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York
Received on Fri Nov 02 2001 - 16:20:40 GMT

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