Secondary MX record?

Hello all,

We have an onsite Exchange server that handles all or our mail. We have a single MX record in DNS that points to it. I want to have a backup mail server through our ISP in case something ever happens to our primary. Can i just create a secondary MX record with a lower priority for the backup mail server? How does that work....all email will still go to our primary mail server and when it becomes unavailable for whatever reason, all mail starts routing to the secondary mail server until the primary comes back online? Thanks in advance!
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Not aas simple,
it's not automatic,

if your primary server is down (or reject the mail for antivirus reasons or antispam, or ...), the mail try to be delivered to the secondary MX.

you need to ask your ISP to do

you need to ask your ISP to do this job (accepting your emails and relaying them when the primary server come back)

but most of them do this job without any problem.
Any professional ISP can host a mail fall-back service for you. When your mail server is unreachable for X attempts, the remote mail hosts will deliver mail to the secondary MX instead of returning it as undeliverable.

How mail is delivered when your server is back up depends. Sometimes this is automatic (because the mail host tries to push mail after some delay) or you'll have to use ETRN to signal the secondary MX that you're back online.

So, ask your ISP if it offers mail fallback for your domain.

Note that fallback only applies when your server is unreachable; a rejection because of viruses, spam, incorrect addresses, etc. will not deliver mail to the fallback host and the message will be returned undeliverable.
Note that a lot of the spam sent these days is sent to your backup MX record first, then it tries the primary record if it has to. They do this because the backup mail servers commonly don't have the same level of anti-spam filtering that the primary ones do. If you notice more spam than usual, you'll want to make sure your ISP, or who ever is hosting your backup mail server, has anti-spam filters similar to your primary server's filters.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.