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aussie-isp /
2006-04
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Date: Wed, 19 Apr 2006 01:07:07 +1000
From: Sean Winn To: Edwin Groothuis Cc: aussie-isp, aussie-isp Message-Id: <000001c662f9$c3021470$2522630a@t22> In-Reply-To: <20060418105458.GA1102@k7.mavetju> Subject: RE: [Oz-ISP] SPF Records |
Followups: <20060418230605.GB12751@taz.net.au> |
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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 That's obviously not the case elsewhere; so right now, SPF still has low value overall, as '?all' or '~all' will be common. And that was the question Jessica poses (mostly rhetorically; I was just replying with big examples showing how little it has, regardless of what is done in this country, or written into codes of practises) That's not to say it has zero value - where it is being definitive it can be taken advantage of. ---- 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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