*BSD News Article 48612


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From: peter@haywire.DIALix.COM (Peter Wemm)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Problem with ifconfig alias
Date: 14 Aug 1995 18:45:14 +0800
Organization: DIALix Services, Perth, Australia.
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References: <400tlf$5na@alpha.aladdin.co.uk> <402kj1$jv6@nnrp1.primenet.com> <407abb$puq@buffnet2.buffnet.net> <408b4u$bf3@park.uvsc.edu> <40ccac$3a6@bonnie.tcd-dresden.de>
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j@bonnie.heep.sax.de (J Wunsch) writes:

>Terry Lambert  <terry@cs.weber.edu> wrote:

>>] : >>ifconfig ed1 193.119.96.55 netmask 0xffffffff alias

>>Is there a good reason that the 0xffffffff netmask should not
>>*ALWAYS* be implied by the use of the "alias" keyword?

>It should be made the default netmask for `alias', thus it's still
>overridable for those who need it.

Just a reminder.. There's two uses for 'alias'
1: multiple presenses on the *same* subnet (eg:virtual web server), in
which case the 0xffffffff netmask is needed.  This is because the
netmask is "completely specific" and overrides the route to the main
address in the radix tree.
2: multiple presenses in different subnets on the same wire.  In this
case you need the correct netmask for each subnet.

I suspect that changing the default will quiet half of the FreeBSD camp, and
suddenly cause problems for the other half, causing them to start
complaining....

Perhaps this:  *if* the alias address is contained within the subnet of the
primary interface address, then change the default to 0xffffffff.  I
think that would solve 99% of the problems, without creating new ones.

IMHO, a blanket change to 0xffffffff default for 'alias' isn't
ideal...

Cheers,
-Peter

>-- 
>cheers, J"org                      private:   joerg_wunsch@uriah.heep.sax.de
>                                   http://www.sax.de/~joerg/

>Never trust an operating system you don't have sources for. ;-)