Topic: BackupMailServer - 2nd location for redundancy?

[k_graham]

If one has the email server go down normally it picks up the email when its back up and running.

However I was wondering about the possibilities of designating a 2nd location possibly with a 2nd service provider as a Mail server so if the 1st was down the mail would go there.

These would be designated loc1.domain.com and loc2.domain.com where domain is the name of the website. So if using Thunderbird to access mail would 1 perhaps only need a 2nd mail account enabled so that say mail was sent to smith@domain.com it could be retrieved by having Thunderbird look to smith@loc1.domain.com and smith@loc2.domain.com ?

Next would it be possible to have the mail go to the 1st by preference if server not down, thus when emails start to show up in the loc2 inbox one realizes there is a problem with loc1 .

I ask as we changed from Cable to Fiber last week, the change was flawless for a week, then the new provider flicked a software switch and  we no longer received emails yet our Internet was up, our email was down for a few hours before we could pinpoint the provider as the problem, it took a total of 24 hours to resolve completely though.  I had intended to have both locations using Fiber but am now tempted to keep 1 on Cable for 2 service provider backup.

(this was the time of the Hurricane in the U.S. and I thought initially it could be a DNS issue above my local provider - it was not)

Thanks, Ken

[guest22]

Maybe the wiki can help https://wiki.contribs.org/Email#Secondary.2FBackup_Mail_Server_Considerations

[ReetP]

I think you might be trying to conflate a couple of different issues here.

You also haven't really explained your setup very well... you have two locations ?

Exactly what DID happen with the ISP ? You say it wasn't a DNS issue, but assuming you had internet connectivity, and the IP address and DNS correctly configured, I don't see why your mail didn't get delivered ?

You say "I had intended to have both locations using Fiber but am now tempted to keep 1 on Cable for 2 service provider backup."

That really doesn't make any sense at all If you have two locations, and each one has one connection, then swapping from Cable to Fibre probably makes no difference at all, unless you mean that you would have two different providers so are not reliant on one. However, that then doesn't solve your issue if the main location with your mail server goes down.

A well behaved mail server will attempt to deliver mail, and will hold it if it can't get to the correct destination. Running you own MX backup (there is a SME contrib to configure an SME server as a MX backup server) means that mail will be delivered to a server in your control prior to forwarding on to the final destination in the event of issues.

All well and good there.

However, you then want to be able to access the mail on the backup MX server. Not so easy - remember the MX backup is just holding mail in a pool to forward on - it doesn't actually process anything per se.

To do that you are really talking about high availability which is another thing entirely. The two mail servers have to be able to communicate and sync so if one goes off the other picks up.

Your only simple solution is to run SME on a cloudy box. Quite a few of us run SME as a virtual machine in the cloud (I have my own cloudy server running Proxmox  with a number of SME VMs). I decided to migrate to that solution for our work mail when we moved abroad and effectively had two offices.

Another alternative is to make sure the location with your mail server has a second internet connection as backup. If you have one location with two internet connections then you can set one IP as the primary and the second IP as the backup - I use this for my home email. I think to get Thunderbird to then access either of the IPs would need a bit of DNS trickery but is doable.

Anyways, if you can describe your situation a little more then we may be able to give you some more advice.