Sending Domains

Sending domains are the domains that appear in message headers and the email appears to be sent from these domains. Once you add a sending domain, Mumara generates DNS keys to authenticate the domain.

Menu Navigation: Setup - Sending Domains

List Sending Domains

On this page, you can see all of the sending domains that you have added so far along with table options.

Table Fields

Field Description
Sending Domain The domain name to send from
Tracking Prefix The subdomain that will appear behind all hyperlinks and images for tracking purpose
Redirection Type Displays the redirection type you have selected while adding the sending domain
DKIM Success: Displays a green tick if the public domain key was resolved
Failed: Displays a red cross if the public domain key wasn't resolved
Redirection Success: Displays a green tick if the redirection is working fine
Failed: Displays a red cross if the redirection isn't working fine
Added on Date when this sending domain was added
  • Set Ownership as Verified: Set domain's ownership as verified forcibly
  • Verify Public Domain Key: Recheck public domain key
  • Verify Redirection: Recheck tracking domain redirection
  • Download Domain Key Pair: Download domain key pair for DKIM
  • Delete: Delete the sending domain

Add a Sending Domain

Click on [+ Add New] button to add a sending domain.

In the snapshot, I have used a sample domain
In the snapshot, I have used a sample domain
  • Sending Domain: Insert the Sending Domain that you want to add
  • User Secure URL: If enabled than Mumara will sue HTTPS protocol for the tracking domain
Once you click [Add] button, you'll be directed to the domain details page to authenticate it

DKIM Authentication

DKIM, also known as Domain Key Identified Mail associates a digital signature of the domain name with email headers and vouches for the authority. The sending mail transfer agent (MTA) generates the signature by using an algorithm applied to the content of the signed fields. This algorithm creates a unique string of characters or a “hash value”.

Generate Public and Private Domain Keys

Turn the switch on to generate the public and private domain keys pair. When you enable it, it will show you a popup asking for confirmation and upon approval, it will generate a key pair for the associated sending domain.

Download Key Pair

Click on the download icon to download the domain key pair. The downloaded zipped file contains a public and private key file separately.

Public Domain Key

The public domain key consists of three parts.
  1. Selector
  2. Domain Key Universal Identifier i.e. _domainkey
  3. Domain Name
So the fully qualified domain to store public domain key becomes "".
Selector: By default, Mumara shows "key" for the selector value that can be edited as well. You can also edit this default value in Application Settings under the "Sending Domains" tab.

When an email is received, the destination mail agent reads the message headers for the domain key signature and finds the signatory domain name and selector to fetch the public DNS record of it. Upon successful handshake of public and private domain keys, the mail is identified to be sent from the legit domain.

Where to Add Public Domain Key?

You'll need to find out where the DNS zone of your domain name is hosted. It can be within a hosted control panel on your server or your domain registrar or a third-party e.g. Cloudflare, DNSmadeeasy, ClouDNS, etc. Moreover, you can also find the nameservers of your domain name to identify where the DNS is hosted.

Go to the domain's DNS and find the place where you can add records. The record under the HOST column that you see in Mumara as shown in the picture above has to be inserted as a subdomain/host in domain's DNS and the content you see under VALUE column has to be inserted/pasted into the content field of the DNS as a TXT record type.

The snapshot was taken from Cloudflare

In the above snapshot, I am adding the public domain key that Mumara has generated for the domain

Regenerate Keys

Although it's a rare scenario that you would need to regenerate the domain keys but you still have an option if you want to regenerate the domain keys pair.

Private Domain Key

Private Domain key can be utilized in two ways
  1. Mumara signs outgoing messages
  2. Your MTA signs outgoing messages

1. Mumara Signs Outgoing Messages

As appears in the snapshot above, if you turn the switch on to make Mumara sign your outgoing messages then Mumara will embed the digital signature for all outgoing messages.
ESP Cases: If you are using an Email Service Provider (ESP) then almost all ESPs sign outgoing messages themselves and provide their own public key for your domain. In such cases, you don't have to generate Domain Keys in Mumara. If you have already generated the domain keys in Mumara then make sure that the "Sign Outgoing Emails" switch is disabled, otherwise, there will remain a conflict and both signatures will be stamped that may result in DKIM failure.

2. Your MTA Signs Outgoing Messages

This case is mostly for the people who are using SMTP service or their own SMTP solutions. In this case, you'll need to find out in your MTA software on how to embed private domain key for the outgoing messages. So you'll need to store the private domain key file on your MTA server and define its physical path as per MTA configuration format.

Below you'll find an example of adding private domain key in PowerMTA. Edit PowerMTA config file and insert the following line
domain-key key,,\etc\pmta\dkim\
So PowerMTA will take the responsibility of signing all outgoing messages.

Key Size

The default domain key size that Mumara generates is 1024 bits. You can change the key size in Application Settings under the Sending Domains tab as appears in the snapshot below.


Tracking Domain

The tracking domain is a subdomain of your main sending domain that is used for tracking purposes and appears behind all hyperlinks and images instead of Mumara's main domain. It also white labels your email content with the associated domain. Be default Mumara uses "click" as the tracking domain prefix that can be edited according to your choice.
Prefix: If you want to change the default prefix, you can do that in Application Settings under "Sending Domains".

Redirection Methods

Two types of redirect methods are mentioned in Mumara. However, there could be custom solutions as well.
  1. CNAME
  2. htaccess


CNAME is a domain-based redirection that maps the source domain to the destination domain and displays the content of it. In order to make it work you need to take care of the following two things
  • Add a CNAME record in your domain's DNS
  • Add an entry of tracking domain in your web server
To add a CNAME Record, login to your domain's DNS zone and add a CNAME record as it appears in Mumara.

Taken from Cloudflare

The snapshot above shows the CNAME record being added for the domain

So once the CNAME record is added, it means the sourcing domain has started pointing to the destination domain's server. But in most cases, the destination server doesn't recognize the sourcing domain and redirects it to the webserver's default page instead of navigating to the correct path of Mumara installation. So in such cases, you need to play a bit more and add this sourcing domain to your web server as well and map it to the correct physical location where Mumara is hosted. Once Mumara sees a handshake from both sides, it will verify the redirection.

2. htaccess

It's a simple redirection method where you host the tracking domain on your server and upload the htaccess file content that Mumara gives you.
  1. Click to download the .htaccess file
  2. Extract the zip file
  3. Upload the .htaccess to the tracking domain's root folder
Tracking Domain: You can still host website content on your tracking domain as your .htaccess rules are just applied to certain matching URLs.


Confirming DNS Records

Once you are done with adding the DNS records, click on the green "Confirm" button to validate DNS propagation.

  • Success: If Mumara is successful validating the DNS records then you'll see a green tick here
  • Failed: If Mumara fails to validate the DNS records then you'll see a red cross here



There is a blue [Recheck] button that makes Mumara retrieve the DNS records again and revalidate them.

Useful Links

Why Your Tracking Domain Isn't Verifying