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Date: Wed, 19 Apr 2006 10:36:22 +0930
From: Alex Wilkinson
To: aussie-isp, aussie-isp
Message-Id: <20060419010622.GA69277@squash.dsto.defence.gov.au>
In-Reply-To: <000001c662f9$c3021470$2522630a@t22>
References: <20060418105458.GA1102@k7.mavetju> <000001c662f9$c3021470$2522630a@t22>
Subject: Re: [Oz-ISP] SPF Records
No followups recorded.

    0n Wed, Apr 19, 2006 at 01:07:07AM +1000, Sean Winn wrote:

    >m a j o r d o m o - o w n e r @ k o a l a . a u s s i e . n e t wrote:
    >> On Tue, Apr 18, 2006 at 08:03:14PM +1000, Sean Winn wrote:
    >>> m a j o r d o m o - o w n e r @ k o a l a . a u s s i e . n e t wrote:
    >>> ip4:152.163.225.0/24 ip4:205.188.139.0/24 ip4:205.188.144.0/24
    >>> ip4:205.188.156.0/23 ip4:205.188.159.0/24 ip4:64.12.136.0/23
    >>> ip4:64.12.138.0/24 ptr:mx.aol.com ?all"
    >>> aol.com.                300     IN      TXT     "spf2.0/pra
    >>> ip4:152.163.225.0/24 ip4:205.188.139.0/24 ip4:205.188.144.0/24
    >>> ip4:205.188.156.0/23 ip4:205.188.159.0/24 ip4:64.12.136.0/23
    >>> ip4:64.12.138.0/24 ptr:mx.aol.com ?all"
    >>>
    >>> Same for gmail.com; yahoo.com doesn't even have SPF. Hotmail is
    >>> slightly different... ~all as a soft fail instead.
    >>>
    >>> Value of SPF? Very little except for being feel-good about forged
    >>> email. Spammers can use SPF as well, with throw-away domains, and
    >>> probably do.
    >>
    >> SPF isn't an anti-spammer tool, it's an anti-forgery tool. I don't
    >> care if spammers use their own throw-away domains for it. I do care
    >> if spammers/viruses use my address as the sender address.
    >>
    >
    >Certainly is. But if it's not definitive, what's its value?
    >
    >> The above examples give a good idea of the fine-tuning SPF is capable
    >> of.
    >>
    >> -   With -all, it says: "These ip addresses, that are our outgoing
    >>     SMTP servers. Dont' trust anything else".
    >>
    >> -   With ~all, it says: "These ip addresses, that are our outgoing
    >>     SMTP servers. I wouldn't trust anything else if I were you, but  
    >> it is possible."
    >>
    >> -   With ?all, it says: "These ip addresses, that are our outgoing
    >>     SMTP servers. But it can come from other places."
    >>
    >
    >Only '-all' is definitive. And 4 major domains used for mail say they
    >can't be definitive. So they don't seem to place a high value on SPF for
    >themselves.
    >
    >
    >> For my domain (mavetju.org), it says -all. For the domains we host,
    >> it's -all. We offer our clients authentication SMTP delivery on a
    >> non standard SMTP port. There should be no reason for them not to use
    >> our mail servers.
    >>
    >> Edwin

some interesting comments about SPF: http://archives.listbox.com/735/200403/0463.html

-aW
----
email "unsubscribe aussie-isp" to m a j o r d o m o @ a u s s i e . n e t to be removed.

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