Most ISPs and email filtering systems publish guidelines on what they expect from marketers and large email senders. These guidelines are not technical and are well worth a read.
You can find these guides by searching for the name of the ISP or filter and adding either postmaster or bulk sending guidelines.
These guidelines have been compiled with help from our email deliverability partners, Return Path.
ISPs
Microsoft
| Domains managed |
and any country-specific variants of these domains. |
| Allowlisting availability | Microsoft does not provide its own allowlist to mailers but does use the Return Path Certified allowlist. To find out more information about the service, speak to your Client Success Manager. |
| Feedback loop availability | The Junk E-Mail Reporting (JMR) Partner Program is the Microsoft feedback loop. The goal of Junk E-Mail Reporting (JMR) Partner Program is to help organizations maintain mailing best practices by unsubscribing unwanted recipients and ensuring clean mailing lists. To get started, fill out the form at: https://postmaster.live.com/snds/JMRP.aspx?wa=wsignin1.0 |
| Authentication used | Microsoft authenticates using SPF and DKIM. |
| Typical problems encountered |
Bulking due to poor reputation factors that include complaints, unknown users and engagement. High volumes of mail determined to be 'spammy' by Brightmail (see known filters, below) may cause a sender's IP address to be blocked as well. These blocks last for 24 to 48 hours and are then removed. If the large majority of mail originating from the IP is marked as spam by Brightmail it will be blocked again, and so on indefinitely. In this scenario, it is not Microsoft's system that is blocking the IP address but Brightmail's. The only way to stop this process is to contact Symantec, not Microsoft, to have the block removed. To do this, send an e-mail message to: investigation@review.symantec.com After you've sent the request, their team will open the submission and render a judgment, or possibly request additional information. Remember to include the IPs which are being blocked. Until Symantec goes through the process of investigation and renders a decision there is nothing that Microsoft can do to improve the delivery of your messages. |
| Known filters used |
|
| Other sender services |
The Smart Network Data Services (SNDS) is a service provided by Microsoft and allows you to determine why mail is being filtered or blocked. To sign up for this free service, go to: http://postmaster.msn.com/snds/ |
| Contact Information |
If you have had problems sending emails to Microsoft users please use the resources at http://postmaster.live.com or https://sendersupport.olc.protection.outlook.com. At this site you can receive answers to some common questions as well as access Support. The average response time is 2-4 days. |
Gmail
| Domains managed |
and any country-specific variants of these domains. |
| Allowlisting availability |
No details provided. |
| Feedback loop availability |
No details provided, but Gmail supports the List Unsubscribe function. Currently Gmail only supports the mailto option of List Unsubscribe. The unsubscribe option will only be available to a recipient if the sender authenticates with SPF and DKIM, uses the mailto list unsubscribe, and has a good reputation |
| Authentication used |
Gmail verifies and publishes SPF and DKIM records. Gmail filters inbound mail based on authentication and provides the pass/fail results for these authentication checks in the headers of the raw message source. To access the message source, drill down to the Gmail seeds. Authenticated senders receive some positive weighting toward placement in the inbox. |
| Typical problems encountered |
The most common problem at Gmail is bulking. Senders who experience bulking at Gmail should focus on list quality and content testing. Since Gmail does not provide a feedback loop, removing inactive subscribers is one of the most effective ways of reducing complaints and improving inbox placement rate. Gmail does occasionally block mail, usually with one of the following errors:
|
| Known filters used |
No details provided. |
| Other sender services |
No details provided. |
| Postmaster website |
http://www.google.com/gmail/help/bulk_mail.html |
| Contact Information |
Gmail does not provide a postmaster support function for senders. |
Yahoo!
| Domains managed |
and any country-specific variants of these domains. |
| Allowlisting availability |
Yahoo! does provide a allowlist. To apply for the Yahoo! Allowlist, complete the form at: http://add.yahoo.com/fast/help/us/mail/cgi_bulkmail The Postmaster will respond with an application to be completed and submitted via email. |
| Feedback loop availability |
Yahoo! offers a domain-based Complaint Feedback Loop service, free of charge. Yahoo! Complaint Feedback Loop. |
| Authentication used |
Yahoo! checks inbound mail for SPF and DKIM. If you have a DMARC policy in place, Yahoo! will check it and block mail accordingly. |
| Typical problems encountered |
Yahoo! filters email based on user feedback, traffic and reputation history, authentication, content, and engagement. Mail not meeting Yahoo! standards is generally delivered to the Junk folder. For senders with insufficient reputation or sending history, deferrals are common. Blocks can also be triggered by content. |
| Known filters used |
Yahoo! uses a home-built suite of anti-spam filters called SpamGuard which learn "spammy" content through user complaints. |
| Other sender services |
No details provided. |
| Postmaster website | The main postmaster can be found here: https://help.yahoo.com/kb/postmaster. |
| Contact Information |
For bulking issues, senders can contact Yahoo by clicking the Contact Us link on the Yahoo Postmaster website. Yahoo usually replies with a canned response directing senders to the postmaster website resources, as most bulking is a result of reputation. |
Mail.ru
| Domains managed |
mail.ru and my.com (similar to Alto Mail). |
| Allowlisting availability |
Mail.ru does not provide its own whitelist to mailers but does use the Return Path Certified whitelist. To find out more information about the service, speak to your Success Manager. |
| Feedback loop availability |
Mail.ru offers a public FBL here: https://postmaster.mail.ru. Note: Return Path offers allowlist and feedback loop management services; contact your Success Manager for further details. |
| Authentication used |
Mail.ru authenticates using DKIM and SPF. |
| Known filters used |
Mail.ru's spam filters are built in-house. They do not share the details of their spam-filtering methodology. |
| Blocks and error messages | Mail.ru provides a list of their sending requirements, as well as possible causes for blocked messages: http://help.mail.ru/enmail-help/postmaster/error Note: Non-Russian speakers will require Google Translate. To request removal from the mail.ru blocklist, go to: http://win.mail.ru/cgi-bin/support_bl?lang=en. |
| Postmaster website | Mail.ru's official postmaster page: http://postmaster.mail.ru. |
| Contact Information |
Contact mail.ru at: postmaster@mail.ru. |
Web.de
| Domains managed |
web.de |
| Allowlisting availability |
web.de uses ECO/CSA (Certified Senders Alliance). Information about web.de's filtering methodology can be found here: http://postmaster.web.de/en/best-practice/ |
| Block removal |
web.de has listed their error messages with definitions here: http://postmaster.web.de/en/error-messages/ and has provided the following form for block removal request contact: |
| Feedback loop availability |
web.de uses Echo FBL services. |
| Authentication used |
web.de authenticates using SPF and DKIM. |
| Known filters used |
|
| Postmaster website | The official web.de postmaster page is located at: http://postmaster.web.de/en/. |
| Contact Information |
http://postmaster.web.de/de/kontakt/. |
