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SubjectRe: notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias
Matthias Andree <> writes:

>On Thu, 06 Sep 2001, Alan Cox wrote:

>> If you accept from the outside you are leaking information. It

>No, if you accept 10.*.*.* from the outside, your routers are broken.

BS. This has nothing to do with "accepting connections from addresses":

% telnet smtp
Trying <---- Note!
Connected to
Escape character is '^]'.
220 ESMTP Sendmail 8.11.6/8.11.6; Fri, 7 Sep 2001 11:00:01 +0200
250 Hello [], pleased to meet you
250 2.1.0 <>... Sender ok
RCPT TO: <henning@[]>
550 5.7.1 <henning@[]>... Relaying denied
RCPT TO: <henning@[]>
250 2.1.5 <henning@[]>... Recipient ok
RCPT TO: <henning@[]>
550 5.7.1 <henning@[]>... Relaying denied

You may guess now, which the _real_ IP address of ""
is. Yes, "that other mailer" leaks this information. But only for its
own, local IP address.

More "real world" you can't get as in this example. The box transfers
about 1000 Mails per day which may not be much in todays internet but
is fine as "my little mail home". Percentage of failed mails because
of [ip-addr] adressing: 0.00%

So where lies the problem with all this? If the current reporting of
the netmasks is a bug: Fine, fix it, get on with life.

I agree totally with Alan here. If the config can be reported by the
4.3 API, then it should be and be correct. If it can't: Well tough
luck for "really, really" portable mailers.


Dipl.-Inf. (Univ.) Henning P. Schmiedehausen -- Geschaeftsfuehrer
INTERMETA - Gesellschaft fuer Mehrwertdienste mbH

Am Schwabachgrund 22 Fon.: 09131 / 50654-0
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