Re: notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19]

[Charles Cazabon <linux-kernel@discworld.dyndns.org>]

Wietse Venema <wietse@porcupine.org> wrote:
> 
> An SMTP MTA is required to correctly recognize user@[ip.address]
> as local.  That's the rules, like it or not. These address forms
> are actually being used, like it or not.

Yes.  MTAs have to work around this; qmail does a reasonable job.  Why
not look at how djb does this?  See ipme.c.
 
> It also is desirable for an MTA to treat clients on local subnets
> different than strangers that happen to be on the same class A,
> like it or not.  Failure to do so can make one end up on black
> lists, like it or not.

Having an MTA automatically treat clients on "local subnets" differently
than the rest of the 'net at large is definitely _not_ desirable.  The
administrator should have to explicitly configure the MTA to grant
additional access to every subnet he desires; anything else is begging
for trouble in the form of absued relaying privileges.
 
Charles
-- 
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Charles Cazabon                            <linux@discworld.dyndns.org>
GPL'ed software available at:  http://www.qcc.sk.ca/~charlesc/software/
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