SMTP: how to avoid ending up in spam?
The SMTP server is used to send your emails. You need to understand how it works if you want to get past the anti-spam filters. What criteria does it use to deem an email to be spam? And how much leeway do you have with the SMTP server to maximise your chances of delivery? All good emailing techniques need to be studied closely. In focus.
What is an SMTP server / POP server / IMAP email server?
SMTP stands for Simple Mail Transfer Protocol. The SMTP protocol is used to send electronic mail.
To receive them, on the other hand, a POP - for Post Office Protocol - or IMAP - for Internet Message Access Protocol - protocol comes into play.
These POP and SMTP servers are those of your ISP (Internet Service Provider): Google, Yahoo, Free, LaPoste, AOL, Numericable, etc.
What should I choose between POP or IMAP?
POP or IMAP? IMAP or POP? What's the difference between the two? IMAP lets you access your messages from any device with an Internet connection: your e-mails remain on the server.
IMAP is gradually replacing POP, which is designed to access your emails by transferring them to your device.
SMTP and spam
To avoid your e-mails being considered as spam by the incoming mail server, your mailings must meet a certain number of criteria.
And it's particularly when it comes to configuring your SMTP server that you need to take action.
What is spam?
Spam is unsolicited and unwanted communication containing, for example, virus download links.
Spam status can be given to an e-mail, which will be blocked in the future, by :
- the recipient, who reports it manually ;
- the Mail User Agent (MUA) spam filter.
- Webmails: also known as email reception servers. They are accessed via the Internet. They include Gmail, Yahoo, Orange, SFR, OVH, etc.
- Email client: this is email software installed on your computer. There are several, the best known being Mail, Microsoft Outlook, Windows Live Mail, Apple Mail and Mozilla Thunderbird.
How can you prevent your emails ending up as spam? Two tips
Avoid port 25
You can choose your server port. Depending on your ISP, between one and three are available: port 25, 465 or 587.
The port you choose determines the secure connection mode to your SMTP server. This mode can be secure: using passwords as on port 465, or auth on 587, or open as on port 25.
With the problems of identity theft associated with an open port, ISPs often refuse mail from port 25.
Choosing the right sender email address
From which e-mail address should you send your mail? If it's a mass mailing, such as a newsletter or mailing, using your own address is not necessarily a good idea.
It runs the risk of being inundated with replies, out-of-office messages, hard bounces and soft bounces. Use another one then... but which one?
Choose one or create one, associated with a user name and your domain name - like contact@votredomaine.com.
Avoid server administrator addresses such as postmaster@votredomaine.com.
The history and correspondence between the domain and the SMTP server are points that anti-spam filters look at carefully, so reuse your address from one campaign to the next.
SMTP and spam: what's at stake for your company?
The threat of the blacklist
When your e-mails go to spam, you damage the reputation of your IP (Internet Protocol) address. Mail servers are based on lists.
By sending emails without taking care to comply with their anti-spam criteria, your IP address can find itself blacklisted. And once the damage has been done, it is all the more difficult to undo.
The choice of SMTP mail server
In the event of an impasse, if your e-mails are systematically considered to be spam, it's your SMTP server that you need to contact.
Action needs to be taken upstream, at source. That's why it's so important to choose an SMTP server that can provide you with support and a quality email service when you need it.
Emailing software solutions
Marketing solutions for mailing work with shared IPs. A bad practice perpetrated by one user can have repercussions on the others.
Publishers are therefore particularly vigilant. Whether it's SimpleMail, Sarbacane, ActiveTrail or SendinBlue, they all offer a set of best practices already integrated into the tool, and take care of configuring the SMTP server to maximise the deliverability of your mailings.
Your SMTP server, which is responsible for sending your emails, needs to show its credentials to webmails and your recipients' email clients. So you need to configure it accordingly.
When using a mailing solution for your mailings, delegate this task to a specialist who will guide you in your choices and ensure the good reputation of the IP address associated with your mailings.
Article translated from French