Hello Benoit,
On 14. 03. 11 14:49, Benoit Panizzon wrote:
We got two customers (one is another ISP) pretending that they have observed, that Google, Sunrise and other Services have startet flagging their customer's emails as spam, because the sender domain has not SPF record. Not an 'non matching' SPF record, but the sender just dones not use SPF at all.
Hotmail has been doing it for a long time, so it is no new matter for mail providers.
If your customers can use foreign SMTP servers to send emails, you can instruct your SPF record to include this info, by simply syaing what you advertise as your "normal" outgoing servers is not exclusive (-all vs ?all).
Remote ends can increase their confidence depdending on the source, by decreasing/increasing spam score, bypassing greylists, etc...
If your SPF record is correct, you don't really need to know if it's usefull or not, it is simply harmless and provides additionnal info to remote parties.
As a conclusion, if you care enough for your customers, you _should_ publish accurate SPF records for their (your) domains, whether you use SPF in your filtering techniques or not.