Custom sending domain

What are sending domains?

A sending domain is the domain from where emails are delivered. Back in Stock currently uses the default sending domains backinstockemail1.com and backinstockemail2.com. Note that those domains are not the same as the domain in the From field, that is possible to edit it in the email template.

Technically, it is the domain that it is in the Sender and Return-Path email fields. It is important for DKIM and DMARC.

Should I use a custom sending domain?

A sending domain is only necessary if you have DMARC set in your servers with the policy p=quarantine or p=reject. Those values require the domain in the From field to be the same as the Return-Path. Since Back in Stock uses backinstockemail1.com and backinstockemail2.com in the Return-Path, they will be different.

Another reason to have a custom domain is to avoid some email clients to add labels like "via" or "on behalf of" on the emails because it is using a sending domain different from the "From" email. But keep in mind that this does not affect deliverability, it is just cosmetic.

Requesting a custom sending domain

If your server has DMARC policy set to p=quarantine or p=reject and it is not possible to add our IP as an exception, a custom sending domain should be configured. In that case, please contact Back in Stock support. The steps will be:

(Back in Stock) We will add the domain to Mailgun service, that we use to deliver notifications.
(Back in Stock) We will supply the DNS information that you should include in your servers.
(You) Add SPF, DKIM, MX records we provided to your DNS server.
(Back in Stock) We will automatically verify if the DNS records were properly configured.
(Back in Stock) We will update the sending domain for your account to the newly created custom sending domain.
(You) Change the from field of the email template to use the new custom domain, if it is not set already. Read below why a subdomain instead a root domain is preferable (but not required).
(You) If you changed the from field to use a subdomain, set the Reply-To field to an email that can receive the replies from the users. This field is only visible if your account is using a custom sending domain.

Why subdomains?

When setting up a custom domain it is recommended to use a dedicated sub domain (eg backinstock.acme.com ) rather than the root store domain (eg acme.com ). There’s two reasons for this:

Mailgun only allows a domain to be setup by one Mailgun account at a time. If we add acme.com for a customer to Mailgun, and later on another app (or the store itself) wants to use Mailgun to send email from acme.com there will be a conflict and Mailgun may remove the custom domain from our account (this may sounds rare, but has actually happened).
If there are any spam or deliverability issues around sending Back in Stock notifications it will isolate the root domain (which is probably used for higher priority email, such as order confirmations) from being affected. This is unlikely, but still a good practice.

Updating DNS records

Please contact your server administrator to set up the DNS records described in the steps above as soon as you receive the data. This is something we don't have access and can't do for you. Once we detect that the DNS records were successfully configured we will change your sending domain and let you know.

It is recommended that you check if SPF/DKIM/DMARC passes after configuring your DNS server: https://toolbox.googleapps.com/apps/messageheader/

Example:

If the custom sending domain is backinstock.supercosmetics.com, the From field should be: [email protected] , and the Reply-To field should be [email protected] (if this email is valid and ready to receive emails).

Why setup MX records?

MX records are recommended for all domains, even if only for sending messages, unless you already have MX records for the domain pointing to another email provider (e.g. Gmail).

As per Mailgun documentation:

Without these MX records in place, you might see an increase in "Sender Domain Verification" errors, which are errors that the recipient server returns whenever your domain lacks MX records. By configuring your domain with MX records (either Mailgun's or an alternate incoming server) the "Sender Domain Verification" error gets a solution, and is prevented from occurring in future cases.

For more info please check the Mailgun help page.