Your web hosting / email server can go down anytime because of scheduled / sudden maintenance, hardware / software / OS crashes, Data center network failure etc.

If you are running an e-commerce website or a website / blog / forum where Emails from your visitors are utmost important to you, than you should definitely consider using a backup Email Service.
How Normal Email Delivery works?
If you are using your own domain name (@yourdomain.com) for receiving and sending Emails, than your hosting account have pre-defined / pre-configured DNS MX Entries or Records.
For example, I am using Google Apps for MrinTech and following are the MX Records I configured in my Web hosting control Panel (cPanel) for all incoming and outgoing Emails:

As you can see in the above screenshot, each MX Entry has a priority assigned to it. Email delivery is first attempted to the primary mail server i.e. the MX Record with lowest priority number. If that particular mail server is not reachable, then delivery is attempted to another mail server with second lowest MX priority number. If the second lowest mail server in priority is also unavailable!, then the mail will be delivered to the server with the third lowest MX priority, etc. This process continues depending on the total number of MX Records with ascending priorities available for your domain name.
Depending on the type of Email Service you are using with your domain, if all the Mail Servers are unavailable because of Server Downtime, Email delivery fails and the Email bounces back to the original sender with mail errors attached within it!
This is where Backup Email Service comes into action.
How Backup Email Works?
Backup Email Service is generally provided by third party websites / services with an additional monthly / yearly payment. The web servers or Email clusters of these third party services are completely isolated from your web hosting server as well as data center.
If all your mail servers are unreachable, then all your emails are sent to Backup email servers. Once they reaches there, they remains in queue and the server continuously reattempts delivery of all the mails to your primary mail server. When your primary server is back online, all Emails in queue are instantly delivered.
Every Backup Email Server keeps on attempting mail delivery to your primary mail server for a certain number of days, after that the Email is bounced back to its original sender and you should seriously consider changing your web hosting / Email provider.
How to set up Backup Email Service for your Account / Domain Name?
For setting up a Backup Email service for your Account / Domain Name, you need to first enter your Domain Name in the Web Interface of Third Party Website offering Backup Email Service and then you need to configure your Domain DNS Records with additional MX Entries.
Once you sign up for a third party backup Email service, by paying their monthly / yearly fees, you will then receive additional MX Records for your domain name and will also get access to their backup email control panel interface.
Recommended Backup Email Service?
I have personally used DNS Made Easy Backup Email Service and it’s one of the best and cheapest available service as of now. If you are considering signing up for Backup Email service from DNS Made Easy, then keep following limitations in mind:
- Each Domain Name is allowed 1 GB of Email data or 100,000 messages in queue. 3 GB, 5 GB, and 10GB options are also available for an additional price.
- Each domain is allowed to transfer 10 GB of email every month.
- There is also a daily limit of 100,000 incoming connections per day.
You can also check out articles for configuring your Backup Email Service using DNS Made Easy here
While writing this post, the pricing for DNS Made Easy Backup Email Service is $12.95 for 1 Year for a single domain name. If you have a Reseller account or want to buy Backup Email service for lots of different domain names, than you may want to directly contact DNS Made Easy.
