SMTP: how to avoid ending up in spam?
The SMTP server is used to send your e-mails. 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 e-mail as spam? And how much leeway do you have with SMTP to maximize your chances of deliverability? All good emailing techniques need to be studied closely. In focus.
What is an SMTP / POP / IMAP e-mail server?
SMTP stands for Simple Mail Transfer Protocol. The SMTP protocol is used to send e-mail.
To receive e-mail, on the other hand, we use POP ( Post Office Protocol ) or IMAP ( Internet Message Access Protocol ).
These POP and SMTP servers are those of your ISP (Internet Service Provider): Google, Yahoo, Free, LaPoste, AOL, Numericable, etc.
What to choose between POP and 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 e-mails 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 intervene.
What is spam?
Spam is unsolicited and unwanted communication, for example containing 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 MUA (Mail User Agent) spam filter.
- Webmails: also known as mail servers. They are accessed via the Internet. These include Gmail, Yahoo, Orange, SFR, OVH, etc.
- e-mail client: this is an e-mail program 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 e-mails from ending up as spam? Two tips
Avoid port 25
You can choose your server's 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 can be password-protected, as on port 465, or authenticated on 587, or open, as on port 25.
Given the problems of identity theft associated with an open port, ISPs frequently refuse mail from port 25.
Choosing the right sender e-mail address
From which e-mail address should you send your mailings? For mass mailings such as newsletters or mailings, using your own address is not necessarily a good idea.
It risks 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 username and your domain name - like contact@votredomaine.com.
Avoid server administrator addresses such as postmaster@votredomaine.com.
Historicity and correspondence between domain and SMTP server are points on which anti-spam filters look closely, 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 become spam, you damage the reputation of your IP (Internet Protocol) address. Mail servers are based on lists.
By sending e-mails without taking care to comply with their anti-spam criteria, your IP address can find itself blacklisted. And once the damage is done, it's all the more difficult to undo.
Choosing your SMTP mail server
In the event of a deadlock, if your e-mails are systematically considered as spam, it's your SMTP server that you need to get in touch with.
Action must be taken upstream, at source. That's why it's important to choose an SMTP server that can provide you with support and quality e-mail 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 SimpleMail, Sarbacane, ActiveTrail or SendinBlue, all offer a set of best practices already integrated into the tool, and take care of setting up the SMTP server to maximize the deliverability of your mailings.
Your SMTP server, in charge of sending your e-mails, has to show its credentials to webmails and your recipients' e-mail clients. That's why 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