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faq:dmarc_spf_considered_harmful

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faq:dmarc_spf_considered_harmful [2017-12-19 12:56]
haa [For email administrators (receiving side)]
faq:dmarc_spf_considered_harmful [2018-12-12 00:09] (nykyinen)
petri.koistinen DKIM on OK.
Rivi 1: Rivi 1:
 ====== DMARC and SPF considered harmful ====== ====== DMARC and SPF considered harmful ======
 +
 +This page is also visible at http://​www.spfconsideredharmful.org ​
  
 DMARC and SPF break many long-time common email usage patterns like forwarding and mailing lists. ​ DMARC and SPF break many long-time common email usage patterns like forwarding and mailing lists. ​
Rivi 15: Rivi 17:
   * SPF might accidently block some SPAM, but that is not its purpose   * SPF might accidently block some SPAM, but that is not its purpose
   * SPF is trying to protect your service against spoofing attacks, i.e., someone claiming to be you and sending emails on your name.   * SPF is trying to protect your service against spoofing attacks, i.e., someone claiming to be you and sending emails on your name.
 +  * SPF does not protect you against [[https://​en.wikipedia.org/​wiki/​Internationalized_domain_name#​ASCII_spoofing_concerns|internationalized domain name]] look-alike domain phishing or spam
 +
 +===== Many internet users forward their emails =====
 +
 +Surprisingly many internet users forward their emails, for example
 +  * to read all their email from a single mailbox,
 +  * forward email from old address to current mailbox address,
 +  * temporarily forward emails to their mobile address while traveling, or 
 +  * use an email forwarding service as their permanent personal address (e.g. university alumni addresses such as alumni.mit.edu,​ professional organisations such as acm.org or ieee.org, iki.fi, and many others).
 +
 +Using the power of email like this is more common for experienced users, thought leaders and high value contacts and customers making it important that you consider the reliability of your email reaching the recipients.
  
 ===== "​Fixes"​ that break things ===== ===== "​Fixes"​ that break things =====
Rivi 38: Rivi 51:
 Especially if you use the strict ''​-all''​ setting, you will experience your own real emails not being delivered to many recipients, as the email arrives via the forwarding email server(s) instead of the original server and thus may not pass a SPF ''​-all''​ check at the final recipient mailbox. ​ Especially if you use the strict ''​-all''​ setting, you will experience your own real emails not being delivered to many recipients, as the email arrives via the forwarding email server(s) instead of the original server and thus may not pass a SPF ''​-all''​ check at the final recipient mailbox. ​
  
-Most people would probably be surprised how many internet users for example forward their emails, either to +The SPF people have a clunky ​proposed ​workaround (envelope address rewriting) for some of these issues, but expecting //everyone else on the internet to change to accommodate me// will not happen, so **you should use at most the ''​~all''​ setting with SPF for your own domain** (SPF ''​~all''​ means SoftFail, i.e. //accept but mark// instead of reject).
-  * permanently to read in a single mailbox, or  +
-  * temporarily to their mobile address while traveling, or  +
-  * use an email forwarding service as their permanent main address.  +
- +
-The SPF people have a clunky workaround (envelope address rewriting) for some of these issues, but expecting //everyone else on the internet to change to accommodate me// will not happen, so **you should use at most the ''​~all''​ setting with SPF for your own domain** (SPF ''​~all''​ means SoftFail, i.e. //accept but mark// instead of reject).+
  
 ==== For email administrators (receiving side) ==== ==== For email administrators (receiving side) ====
Rivi 53: Rivi 61:
 If you can not receive emails you need because of too tight filtering at your email provider, one solution is to use a email provider who works better, e.g. gmail.com If you can not receive emails you need because of too tight filtering at your email provider, one solution is to use a email provider who works better, e.g. gmail.com
  
-If you are an iki.fi member, you can configure iki.fi to forward your email to multiple addresses, and add e.g. gmail.com backup email address, where you can look for messages dropped by the misbehaving email provides.+If you are an iki.fi member, you can configure iki.fi to forward your email to multiple addresses, and add e.g. gmail.com backup email address, where you can look for messages dropped by the misbehaving email provider.
 ===== Automated emails and SPF ===== ===== Automated emails and SPF =====
  
Rivi 61: Rivi 69:
 ===== More information ===== ===== More information =====
  
-More information (in Finnish) at +More information (in Finnish) at IKI:
   * [[faq:spf]] including instructions for ISPs   * [[faq:spf]] including instructions for ISPs
   * [[faq:​grossdharmaalistaus]]   * [[faq:​grossdharmaalistaus]]
   * [[faq:​spamassassin]]   * [[faq:​spamassassin]]
 +
 +More information around the internet:
 +  * http://​david.woodhou.se/​why-not-spf.html (slightly old)
faq/dmarc_spf_considered_harmful.1513688218.txt · Viimeksi muutettu: 2017-12-19 12:56 / haa