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- Prevent mail being marked as spam 4 answers
How to configure an email server so that outgoing emails are not classified as spam? I've spent the entire day on this and I'm puzzled by the results I'm getting.
Among other things, I have:
- Added DNS record for SPF:
v=spf1 mx a ptr ip4:35.666.24.123/32 ?all
- Added DNS record for SenderID:
v=spf2.0/pra,mfrom a mx ip4:35.666.24.123 ~all
- Corrected reverse DNS records (so that when receiving servers want to verify that the IP address sending them mail actually belongs to the domain the mails are coming from)
- Set up my server to sign every message with a DKIM key and added respective DNS records:
_domainkey TXT o=~; email@example.com dkim._domainkey TXT v=DKIM1; p=MIG...QIDAQAB
- Changed the HELO of my server to match the DNS records.
Here is my SpamAssassin score from http://dkimvalidator.com/:
SpamAssassin Score: 2.973 Message is NOT marked as spam Points breakdown: 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid 0.0 TVD_SPACE_RATIO No description available. 0.4 RDNS_DYNAMIC Delivered to internal network by host with dynamic-looking rDNS 2.5 TVD_SPACE_RATIO_MINFP Space ratio
The default threshold for marking as spam is score 5, so I'm barely below it. Throw one "viagra" in there and that's it! ;)
For comparison, here are the results using my ISP's email:
SpamAssassin Score: -0.719 Message is NOT marked as spam Points breakdown: -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [220.127.116.11 listed in list.dnswl.org] -0.0 RCVD_IN_MSPIKE_H3 RBL: Good reputation (+3) [18.104.22.168 listed in wl.mailspike.net] 0.0 TVD_SPACE_RATIO No description available. -0.0 RCVD_IN_MSPIKE_WL Mailspike good senders
I sent the exact same email from both my own server and my ISP's email. Somehow the TVD_SPACE_RATIO_MINFP was flagged with a 2.5 penalty for only the message sent from my own server. According to their wiki, it's "the ratio of spaces to non-spaces in each paragraph". Is this a bug? Or is it counting spaces from metadata as well or something?
According to the validator, my ISP doesn't have SPF or DKIM records. Yet somehow SpamAssassin is giving them -0.7 while giving me 3.0? Also, I'm somehow flagged for invalid DKIM, yet it's not affecting the score? Why am I flagged when the validator also says (in a different section of the results) that the validation of my DKIM resulted in "pass"?
Edit: this is not a duplicate. This question is not about "how to write an email", it's about how to configure an email server. The parts regarding SPF, DKIM and HELO I already covered in my original post and explained the problems I had with them. Such problems are not described in the "duplicate" posts.