Sending spam or unsolicited mail is one of the tasks most pursued today by ISPs.
Operators such as Gmail, Hotmail or Yahoo have very strict filters and it is for this reason that we can find that the sending of legitimate emails is classified as SPAM.
Below we detail a series of operations to be carried out to prevent our emails from arriving as SPAM.
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Most importantly, prevent them from clicking on "Spam"
To identify SPAM, the method used by large operators such as Gmail and Hotmail is the percentage of “complaints” from their users, that is, when the recipient of an email marks it manually as Spam.
If you send emails to Gmail or Hotmail users, and the recipients mark your email as SPAM, the following emails you send (even if they are to other recipients) will also reach the SPAM tray.
If you have already been penalized in this regard, we will explain how to improve your reputation to solve it, but remember that the one who decides if an email is SPAM is the recipient, not you.
The content of the email is important
- Do not put the whole subject in CAPITAL LETTERS and use a coherent phrase (Anti-spam increasingly understand linguistic syntax better).
- If it is a reply or forwarded message, remove all content that is not relevant to the conversation to prevent that “unnecessary” part from triggering the recipient’s antispam. Also, when there are many chained responses, there are often errors in the html that add points to the antispam.
- Avoid putting extremely long signatures, unlike what many think, you should not put the typical contract of “This email is addressed to its recipient …” It is a hoax and will only create problems for you. If you want to point out a legal term, it is better to put a simple link to your website, for example where you expose your clauses related to the GDPR.
- Avoid using “strange” colors in the font of the text. Many antispam may see this as an attempt to hide content.
- The images always try to put them as an attachment. And in case you include them in the html, try to have a code ratio greater than 90% in text regarding to images.
- Send emails in plain text, but if you decide to use HTML, make sure that you also include a “plain text” version in the code and that the HTML is correctly formatted with the right tags, especially when forwarding or replying to many messages, errors can be created in the HTML code formatting of the e-mail. If you are having SPAM problems, it is highly recommended to send the email only in plain text, at least at the beginning to debug errors.
- Avoid putting contact forms on your website, it is better if you tell your users your email address, in this way they will send you an email when they want to contact you and this process will make your email account be included in the whitelist of who has contacted you and the rest of the messages you send to this person should reach them correctly.
Have the server well configured
- Configure the hostname of the VPS: This can be done from the SolusVM control panel. You must make sure that the hostname responds to ping, therefore, there must be an entry in your DNS server that refers to the hostname..
- Configure the reverse PTR: If you have configured the hostname of the server in the previous point, from the SolusVM panel, in the “Network” tab you have the option of declaring the reverse. It is very important to have the reverse declared so that it is possible to verify the legitimacy of an IP. In this way you are indicating to the operators that this IP is yours and that you are responsible for it and that therefore there is someone behind these shipments. Normally spammers don’t declare the reverse to prevent an entire domain from being blacklisted, but if you don’t send SPAM, you shouldn’t be afraid at this point.
- Configure the SPF record at the DNS level of your domain: In this way, you are verifying the legitimacy of your outgoing email server and that no one is trying to send emails from another server pretending to be you.
- Use SMTP and real sender: It is very important that shipments are made using SMTP authentication and that the sender of the email is the email account with which you have authenticated, so whoever receives your email can verify that the account you use as sender actually exists. For example, do not authenticate with an account with your own domain and then put a gmail account as the sender, you must use the same in both cases and if you want the recipient to reply to another account then use the parameter reply-to.
- Don’t use sendmail or PHP’s mail function: Directly related to the previous point. The sending made through the PHP mail function do not have authentication, in such a way that the recipient cannot verify the identity of the sender and it is very likely that these emails are considered as SPAM..
- Landpage on the sending IP: This is to create a page where your company information and contact information are visible to report abuse. For example, if the IP from where you send the emails is: 5.134.112.0, that when entering such IP from any browser you will see your company and contact information. You can see an example here of what our sending server is, as you can see, we report what activity is carried out from such IP and we put contact information for abuse.
- Check Fail-Delivery: Check your sending logs / var / log, if they have many sending errors. It is typical for spammers to scan the internet for email addresses to send SPAM to, but many of those addresses no longer exist. Operators such as Gmail, Hotmail or Yahoo check if you try to send them to addresses that no longer exist, and if you send many messages to non-existent addresses, it is certain that they will consider you SPAMMER and your emails will not continue to enter user’s inboxes.
IP and / or domain reputation
You can check your IP reputation at: https://www.senderscore.org/ (you must be registered for full details) and at https://www.talosintelligence.com/
As we indicated at the beginning of this document, e-mail providers analyze the number of complaints that recipients make “by clicking on the SPAM button.” That is, you send an email to someone and that person when receives your email gives the “SPAM” button. This action not only causes your e-mail to end up in the SPAM tray of the user, but also provides the ISP (Gmail, Hotmail, Yahoo, etc …) this is a reference to reduce the reputation of the IP and the domain from where the e-mail (sender) has been sent.
If you send mass mailing and many of your recipients click on “SPAM” the reputation of your IP and domain will be reduced quickly. For this reason, it is important that you do not send emails to a recipient who is not interested in receiving your emails.
To gain reputation on your IP and / or domain
The key is to receive e-mails, that is, the users of Gmail, Hotmail, Yahoo, etc … make sending to your e-mail accounts, in this way, these ISPs consider that these recipients are legitimate and increase their reputation. IP / domain at the time of sending. Additionally, if you send e-mails that have reached the SPAM tray and the user indicates that “It is not SPAM”, you also gain reputation, in the same way that the more e-mails you send without anyone clicking on “SPAM” Your reputation will gradually increase for this provider.
Do you have all these guidelines configured but your emails arrive as SPAM?
- Register in the JMRP to get reports on your mails in Junk and requests to unsubscribe from mailing lists -> Here
- Register in Hotmail SNDS to check which emails you have sent as SPAM. Include the IP of your server -> Here
- Contact Hotmail this form or this one or by mail to delist@messaging.microsoft.com
- Contact Office365 using this form.
- Read how you should send emails to Gmail accounts -> Here
- Read how you should send emails to Yahoo accounts -> Here
- Contact Yahoo to whitelist your IP with this form -> Here
- Read how you should send emails to AOL accounts -> Here
If you are not a spammer and you need a professional service for sending your emails, do not hesitate to enroll our Managed VPS.
We have a lot of experience with users who send large amounts of e-mail on a daily basis, but we insist, we can only help you if you really DO NOT send SPAM.
