Mail only node configuration questoin

[WebJIVE]

We're looking into the possibility of using mail only node(s) for our current environment. Right now we have two normal (parent) WHMCS servers and one DNS ONLY (node) which is our backup DNS for the other two parent nodes (mail, web, etc.).

Our question relates to the attached diagram.

We're looking to add mail node(s) to offload mail just in case we have a server go down so that email continues to flow. The DNS only provides the backup needed to keep routes functioning normally.

Per a 'lengthy' trial and error with cPanel Level 2-3 support, we have a working configuration for our current DNS cluster -> see FIGURE A

In the attached diagram, our question is, do you have to use one mail node per server or can you have a single mail server managing mail for both parent nodes per FIGURE A or FIGURE B ?

 

[ffeingol]

One of the cPanel staff can confirm, but when we were looking at this a while ago, it was one to one (one mail node per cPanel server).

 

[WebJIVE]

One of the cPanel staff can confirm, but when we were looking at this a while ago, it was one to one (one mail node per cPanel server).

What I was thinking. One mail node to one server node? The node docs weren't clear on that topic.

 

[cPRex]

That's correct - currently the only option is one mail node per cPanel server. It's been mentioned by many users they would like a many-to-one solution, but I'm not sure when that will be available.

 

[WebJIVE]

Thanks! Jetbackup is still working on a backup solution that you don't need a copy on the node to backup email. Backing up email to the parent node isn't practical for storage.

 

[WebJIVE]

If a parent cPanel node goes down, will email still be delivered to the child node so that customers can still send and receive email?

 

[cPRex]

Yes, that is the expected behavior. From our docs at cPanel Linked Nodes Guide | cPanel & WHM Documentation

"Distributed accounts on a linked mail child node

In most cases, all IMAP, POP3, and SMTP traffic for distributed cPanel accounts goes to the mail child node. However, if this traffic arrives at the parent node (for example, cached DNS lookups), the parent node will:

• Create proxy IMAP and POP3 connections to the mail child node.
• Reroute SMTP mail delivery to the mail child node."

With a proper configuration, no mail should end up being routed to the parent machine anyway.