Email Cluster or something similar

tui

Well-Known Member
Jun 15, 2007
145
40
78
Mexico
cPanel Access Level
Root Administrator
Hello all,

It is possible to create a email cluster? I see a lot of hosting companies that offer cPanel Hosting accounts that have their emails clustered (and you create the emails accounts in your unique cpanel account) and they have a lot of mx servers for a simple domain.

What i want to do is something like this:

Have 2 or 3 or more mx servers, so when a user creates an email account in its cpanel account it created in all servers, so there is the main mx server (cpanel server where the hosting account is created and hosted) and if main mx server fails users still can sending and receiving mails through the other emails servers, when main server is back, then all email boxes synchronize to main mx server, same if a 2nd or 3rd mx server fail.

Or is there a way to have a lot of mx servers (with cpanel) that a single cpanel account can use for sending and receiving mail without the need to have a mail server where account is hosted?

I know that there is a request for this in features request section (i already voted for them) but I want to know if someone has implemented something similar or how it is that some hosting companies have several mx servers that use with a single cpanel account.

Thanks in advice
 

brt

Well-Known Member
Jul 9, 2015
105
10
68
US
cPanel Access Level
Root Administrator
That's not how it works. Multiple MX records are receive-only; you can't send out through them, as your client would have the master servername set as the server.

You could look into the "Backup MX" plugin from NDCHost.

Ultimately, as long as your DNS is clustered (easy using cPanel DNSOnly) if mail is sent and your server is down, sending servers will queue mail until your server comes back up. Mail is only dropped if your server is down AND all of your DNS servers are down.
 

tui

Well-Known Member
Jun 15, 2007
145
40
78
Mexico
cPanel Access Level
Root Administrator
I see... the plugin of NDCHost it's somehow practical, but as you said, if our DNS is clustered mail is un queue until server comes back up, NDCHost plugin receive the mail and send to main server when is back up similar but not the same, however none of both solutions allows the client to retrieve the mail and send mails until main server is back up, is there a way to allow clients to continue use mail when main server is down?

Something like NDHost plugin that receives the mail to a Backup /Mail Spooler but with the ability to retrieve and send mail from it while main server back online.
 

brt

Well-Known Member
Jul 9, 2015
105
10
68
US
cPanel Access Level
Root Administrator
Yeah, with the NDCHost plugin, your own (secondary) server would receive the mail and forward on to your primary server when it came back online.

If your primary server is down but your DNS is online, any server trying to send your users mail would fail but WOULD queue the mail for retry. This is pretty practical for most cases because you shouldn't have any extended outages (or any, really, for that matter) anyway.

If you don't have any external DNS servers and just use a couple of IP addresses tied to the same primary server, this is the worst scenario. If your server (and incidentally all of your DNS servers, in this case) are offline, mail sent will hard-fail during your outage and users will receive a "Mail cannot be delivered." message.

Someone else can chime in if they have any ideas outside of what I've mentioned, but as interested in uptime and backups as I am, I haven't found it worthwhile to mess with mail beyond having 4 geographically disperse DNS servers -- but I can't say I routinely experience enough downtime to justify anything beyond this. Are you trying to solve a specific problem here?

Also, keep in mind that when you start storing/forwarding messages, you can possibly end up with SPF problems, etc.
 

tui

Well-Known Member
Jun 15, 2007
145
40
78
Mexico
cPanel Access Level
Root Administrator
Hello Brt,

I have my external dns servers cluster, i have no problem with it and im not trying to solve a specific problem, i want to offer a plus to my clients,

NDCHost plugin is not what im looking for, what i want is a way to allow my clients to use their mail (send and receive) if the main server is down, I rarely have downtime but i want to be prepared in case it happen or if i in a need to change or upgrade (physically) a server, past month i went in a hurry to change hard disks in one server and i left my clients for about 6 hours, everything well fine at the end but i would like to have something extra to offer them for a future.

Perfect solution would be a landing page "Site is in maintenance" and the ability to use mails if a main server goes down thats my goal
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,880
2,258
463
I know that there is a request for this in features request section (i already voted for them) but I want to know if someone has implemented something similar or how it is that some hosting companies have several mx servers that use with a single cpanel account.
Hello,

Here's a link to the open feature request for anyone visiting this thread with the same question:

Complete email server cluster support

Thank you.