Hello,
What is a Backup MX or Mail Spooling service? Mail spooling is a service provided to you by your ISP that enables their mail servers to accept and hold on to your e-mail when your mail server does down. This is a service still commonly offered by mail providers, but I believe it is dated and should not be used unless you have a good reason for it. There are several issues surrounding mail spooling services including:
- You give at least partial control of your incoming mail policies to your ISP
- Spammers tend to target mail spooling services since they typically have weak anti-spam measures in place
- Most modern mail servers are always online and not on dialup connections
- There are more servers to check when troubleshooting mail problems
- Mail spooling can result in "missing" e-mail when your server is down, resulting in...
- Business clients do not get a bounce message from their SMTP relay servers letting them know that the e-mail they sent has not really been delivered yet. This can be important for time critical e-mails.
Most mail servers will try and resend e-mail to your servers for a few days if your server does happen to have a major problem and go offline. I recommend having multiple incoming mail servers in place over having a primary and secondary mail server setup when possible. The only reason I'd use such a service on today's internet is if I had a mail server that by design would not be available on the internet 24/7.
If you were looking for information about backing up the e-mail on your computer please see our e-mail tutorial
How To Backup Your E-Mail.