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Yahoo Submits DomainKeys Draft To IETF

Posted by timothy on from the you-may-be-surprised-to-receive-this-draft dept.

NetWizard writes "According to a mailing list post at the IETF, Yahoo's website and a Wired News story, Yahoo has made the DomainKeys draft public and submitted to the IETF." Russ Nelson explains "Basically, your MTA uses RSA-SHA1 to sign the headers and body of your email and inserts that signature before sending the email. The recipient MTA looks up $selector._domainkey.$domain in the DNS, gets your public key, verifies it, and inserts a notice. There's also a SourceForge project for a DomainKeys library." An anonymous reader asks "It seems to me that it doesn't offer anything more than the Sender Policy Framework by pobox.com, other than doing relay-based signing of the messages to provide the sender verification. SPF has already grown to over 14,000 domains so far and only requires an addition to your DNS to support (from the sending side). Verifying messages on the receiving MTA is as simple as doing a DNS lookup, most MTAs can support SPF now, the code is available and well tested. What advantages to people see in Domainkeys over SPF that are actually useful, and what standard should people implement?"

7 of 350 comments (clear)

  1. SPF breaks Forwarding by Anonymous Coward · · Score: 5, Informative

    I'm the SysAdmin of an ISP. We had to turn off SPF after some users couldn't send e-mail to people that used mail forwarders. For instance, if someone has a domain 'foo.com' that sends all mail sent to it to 'foo@verizon.net', and foo.com resides outside of verizon.net, my users wouldn't be able to send him mail if Verizon uses SPF.

    SPF is junk. The number one priority of e-mail: Legit mail must reach the recipient.

    1. Re:SPF breaks Forwarding by Mz6 · · Score: 5, Informative
      Info from the SPF site on forwarding...

      "Forwarding services and web-generated email sites need to deploy SRS. Pobox.com, for instance, has already integrated SRS into its bespoke MTA using Mail::SRS.

      Hobbyists who provide .forward or /etc/aliases services will also have to get an SRS-enabled MTA.

      Sites that do not do .forward or /etc/aliases forwarding to remote sites will not need to do a thing.

      Once a majority of forwarding setups are SRS-compliant, SPF publishers can change their defaults from "neutral" or "softfail" to "fail". "

      Seems like for fowarding to work.. one method has to become a standard.. And we need to do it right this time. The above text says that everyone would have to install their software to get forwarding to work.

      --
      Hmmm.
  2. Re:Patent Licensing by Anonymous Coward · · Score: 5, Informative
    It's probably better:

    Yahoo! will grant a royalty-free, worldwide, non-exclusive license under any Yahoo! patent claims that are essential to implement or use any Implementations so that licensees can make, use, sell, offer for sale, import, or yodel Implementations; provided that the licensee agrees not to assert against Yahoo!, or any other Yahoo! licensees of Implementations, any patent claims of licensee that are essential to implement or use any Implementations.


    Microsoft's implementation requires you to sign away your right to sue them for any patent claim and doesn't allow you to sublicense the technology (ie: GPL/LGPL/BSD-incompatible). This one is less agressive.
  3. SPF breaks relaying by Mr.+Slippery · · Score: 5, Informative
    other than doing relay-based signing of the messages to provide the sender verification.

    SPF's handling of relays is broken:

    But that breaks forwarding!

    Yes, it does. You'll have to switch from forwarding, where the envelope sender is preserved, to remailing, where the envelope sender is changed. But don't worry, we're working on providing SRS patches for the four major opensource MTAs, so that when you upgrade to an SPF-aware version, this problem will be solved also.

    If DomainKeys takes care of that, I'd choose it over SPF in a heartbeat.

    --
    Tom Swiss | the infamous tms | my blog
    You cannot wash away blood with blood
  4. Re:To understand... by tanguyr · · Score: 5, Informative

    Not only that, but SPF also seems more flexible. Domainkeys seems limited to making sure that the from header was not forged and that the SMTP machine used is on that domain's approved sender's list. Don't forget that SPF allows you to say "any machine may send mail from my domain as long as the mail is digitally signed" - or "any machine with an MX record in my domain may send mail for that domain" (which you could update withoput having to regenerate keys, etc)

    In short - SPF looks like the more elegant solution.

    --
    #!/usr/bin/english
  5. SPF and DK solve different problems by CustomDesigned · · Score: 5, Informative
    SPF validates the envelope from, and can be checked before the DATA phase of SMTP. Domain Keys validates the rfc822 headers, and can't be checked until after SMTP DATA.

    You want to implement both. SPF detects envelope forgeries before you have wasted much bandwidth. You can then use right hand side blacklists on sender domains. Yes, spammers too are adopting SPF. This is OK - those who like spam have something other than instinct to warn them when they are dealing with a scammer instead of a spammer. Those who hate spam can ignore it more efficiently.

    Domain Keys validates the message headers. It protects you against forgeries by users in the same domain - e.g. a spammer on yahoo forging an innocent party on yahoo. SPF can also detect envelope sender forgeries from the same domain in conjuction with SES (Signed Envelope Sender) - which adds a crypto cookie to the local part.

    You should implement SPF first. It is simpler, and eliminates most forgeries before SMTP DATA. SPF requires sepcial consideration for forwarders (SRS - Sender Rewriting Scheme) or whitelisting.

    DK is a good addon for large ISP domains like yahoo and aol, but is broken by forwarders or mail processing tools that modify the body. For instance, my DSPAM bayesian filter adds "tags" to messages.

  6. Why domainkeys is better than SPF by duncanthrax · · Score: 5, Informative

    1. Domainkeys does not break forwarding.
    2. Domainkeys can be used either on the MUA or the MTA, for both sender and recipient sides. This makes it possible to still use 3rd party relays.
    3. Domainkeys spoof-protects the domain in the "From:" header field, which is what Joe Sixpack sees in his MUA application.

    Domainkeys does have the problem that you can't add headers to messages without re-signing them. If you re-sign them you must also rewrite the "From:" header. This will affect mailinglists.

    Domainkeys will not ultimatively solve the spam problem, but it is better than the broken SPF.