Mails sent by redmine from configured gmail id marked as SPAM
I use Redmine 0.9 build on Ubuntu 10.04. Have configured Redmine to send mails to the users by showing that it is from a particular gmail id (Configured in the email.yml file)
However, these emails directly go to 'SPAM' folder and gmail (gmail ids of users) shows a message saying this message might not have been sent by the email address in 'From'.
Is there a way I can make Gmail to understand that these are not Spam mails but originate from a correctly configured smtp / tls instance of a gmail id?
Most of the receiving email servers do some cross-checking to ensure the email is from legitimate sender mail server. SMTP protocol allows anyone to send email from any email id which give spammers a party time, its a big issue.
Most of the reviving email server (including gmail) use SFP record validation mechanism to ensure the authenticity of sender. In simple words, trough SPF record in DNS, domain owner tells the world who all mail servers are eligible to send mail on behalf of their domain mail ids. Its like saying I authorize A,B,C ... server to send mail with my domain. Receiving mail server picks SPF record for domain (for email in To field) and cross checks is the sender mail server is eligible to send email as SPF record, if not then it normally marks it as Spam and sends it to Spam folder of recipient.
Now see if you are sending mail from your own server (IP) with mail id of gmail, on receiving end server will pick SPF record for gmail domain and it will not find your server's IP to be eligible for send emails with gmail id, hence it marks your mails as Spam. You can not getyour server IP added into the SPF record of gmail as that is controlled by Google.
Simple solution for this is to use gmail servers as relay servers. You pass your email to gmail and gmail will further send it to the recipient.