Slashdot Mirror
AOL Tests Sender Permitted From / E-mail Caller ID
securitas writes "ZDNet reports that AOL is testing Sender Permitted From (SPF), 'an antispam filter intended to accurately trace the origin of e-mail messages.' AOL is performing the widescale SPF test with its 33 million subscribers worldwide. The system works by letting recipients use the SPF record to cross-check DNS data associated with AOL's IP addresses and confirm that the message originated from AOL's servers. The system is one of three competing e-mail authentication protocols. The other IP-identifying protocols are the Designated Mailers Protocol (DMP) and Reverse Mail Exchange (RME/RMX). All systems alter the DNS database to let e-mail servers publish the IP addresses that they use to send e-mail."
So what? Microsoft is working on a new secret email technology and they need people to test it. They are paying people for it too! Send this email message to 10 people and receive a check for $50.00 from Microsoft. My friend Tom did it and it really works!
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I've had trouble with spammers doing small runs with my domain name on AOL. Since I've set up SPF, I haven't had a single bounce from AOL-bound spam. It might just be luck, but as far as I can tell, SPF is helping.
This is not a whitelist filter.
It's not any kind of a filter.
It just means that AOL has published SPF records for its mail servers in their DNS entries. Any mail server speaking SPF, receiving mail from AOL.COM, will check the SPF record.
If the SPF record (which will contain the IP addresses of AOL's mail servers) doesn't match the originating IP address of the mail message (as in, a spoofed header) the message is invalid. Then it can be either dropped or bounced or whatever.
If the SPF record matches the initiating IP address (as in the case of a message legitimately sent by the mail server) it's clear and goes through.
I suspect that as the big commercial guys get more and more aggressive in breaking email standards in the name of combating spam, the internet will split into different incompatible email groups: the old-fashioned types (which include many university departments still) who use a text console and a program like pine or elm, and the AOL/Hotmail/Yahoo crowd. To some extent it's already happening: I can barely read some messages sent from MS Outlook, they're formatted so badly, and as a result I'm less likely to reply to them.
The biggest weakness of this system is that it doesn't protect against some user's system sitting on a broadband DSL/Modem line that has a Trojan Horse used to e-mail the spam. AOL's system probably would only encourage more viruses/worm designed to make computers email relays.
Of course if all non-business accounts were prevented from hosting an SMTP server that would help solve that problem, but I don't think that would go over very well with the Slashdot crowd. I'm not even sure where I stand on that issue.
Ok, I give up, why you?
Using muscle to force the Internet into a standard isn't going to work. We need something that *is* a standard, rather than *pushing* a standard upon people.
Standards don't miraculously appear out of mid-air. Standards are created when one implementation of an idea is chosen over other implementations. Unfortunately, as at least one of your examples shows, we see that its not a
Right now, AOL and several other groups are developing an implementation of a Spam-tracking system. Eventually, one of these systems may win out. If/when it does, a standard is born.
I think the problem is larger than the few annoying emails people get everyday. There's two things to consider.
1) Cummatively, spam is not just a headache but can be resource draining. Getting 10 or so a day for ten days if I don't check email leads to 100 emails. It would be one thing if it affected me but I'm not the only one that uses my mail server or ISP. It bogs down the mail server that I use whether it's my work email or my personal one. At work, my company has to dedicate resources to fight spam which costs companies money. My only effective choice right now is to abandon my email address every year so I don't get spam for a while.
2) Spam is not discrimating. Offers that are sexual in nature may be innocuous to me, but for parents that's another matter. They want their kids to learn email but can't do much to protect them from this content besides not use email.
Well, there's spam egg sausage and spam, that's not got much spam in it.
Prevent email address forgery. Publish SPF records for y
The idea behind Internet Mail 2000 is obviously correct. Why waste time on DNS-based approaches when we COULD be developing the Solution?
This presents a problem to those of us who have unreasonably short penises.
Heh. Actually (if I have understood correctly) SPF should prevent anyone from spoofing aol.com as the sender address during the SMTP session. So if a spammer attempts to spoof aol.com and your mail server is SPF-aware, then it would be good for you and AOL because you won't get spam and AOL won't get bounces for the addresses that had problems with delivery (and with spam, problems with delivery are not rare).
At least this is how I have understood it.
It means that any system administrator can configure their mail transfer agent to bin any spam pretending to come from aol.com with a 100% success rate. And this goes for anyone else publishing an SPF record for your domain.
SPF is a proposed standard for a domain owner to tell mailers where mail From: that domain may originate. The domain owner publishes a DNS TXT record for their domain with (at the simplest) list of IP addresses. Participating mail transfer agents can then look this record up and make a policy decision on whether the mail is likely to be legitimate. The presence of an SPF record on a domain at present means that while you still can't be sure when you're handling spam, you can be sure when you have a piece of non-spam because the SPF record tells you so.
SPF is not a wholly original idea (e.g. up "designated mailer protocol"), and certainly not the simplest implementation but the important factor is that its proponent, Meng Wong, is an excellent lobbyer and spokesperson, as well as someone who as the nous to put forward a useful protocol (he founded pobox.com). It's currently at the point where lots of implementation are being written, with the canonical version being Meng's Perl modules. Currently I'm helping to finish the C implementation which will shortly be integrated into qmail and exim.
The tipping point (I hope) will be when a domain not publishing an SPF record or publishing a globaly permissive one will be considered "obviously" untrustworthy. Combining SPF authorisation with a more traditional "From: domain blacklist" will give spammers a very very hard time indeed forging mail. But AOL publishing a record (we hope) shows the way the wind is blowing: the rest of the world does seem to have to change their mail server configuration to keep mail flowing to AOL.
So go on, it's dead easy, publish a record for your domain now. Tell people where your mail comes from. Look, there's even a wizard to help you.