Multiple parent nodes to one or two child nodes (mail)

ITHKBO

Active Member
Jun 23, 2020
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Hello,

Management has asked me to take a look at the possibility to separate the mail services.
They want to create one or two larger mail only servers and redistribute quota for site hosting.

Is it possible to create a setup like below with parent child node functionality at this time
Parent 1,2,3,4 -> childnode 1
Parent 5,6,7,8 -> childnode 2
Parent node examples have no overlap in domainnames or accountnames in above scenario.


If possible how is IP distribution handled.
We want to give every mail domain its own IP for IP reputation, abuse management.
Is this done and managed from parent or child?

With regards to cPanel ELevate Project is the tool capable of handling parent, child node migration or would it have to be run separately on parent and on child.


The following is a question with regards to thirdparty software in the hopes cPanel support has run into it already with other customers.
With regards to Mailscanner Front-end and Configserver Firewall management is this something that could still be handled from the parent or will integration have to be done from childnode or is it known that it is completely unsupported at this time.

Thank you for your time.
 

cPRex

Jurassic Moderator
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Oct 19, 2014
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Hey there! The short answer is "not yet" - according to our docs at cPanel Linked Nodes Guide | cPanel & WHM Documentation

"We do not currently support configurations that link more than one parent node to a single child node."

ELevate has no concept of this process as that is just for the local operating system itself.

In that same guide I linked above, we say this about the mail traffic:

Code:
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.
so you'd want your mail processing tools to be on the child node.
 
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WebJIVE

Well-Known Member
Sep 30, 2007
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This is a great question and we're close to digging deeper into this as well.

Questions I still have:
1. Does the parent or child node handle spam filtering (SPAMAssasign, ASSP, Mailscanner, etc.) at the parent or child mail node?
2. Do we need to continue using Imunify360 on the mail node as well as the parent node or would the cPanel products be good enough to protect the node?

I realize that a mail-node is just a designation when installing a cPanel server vs the DNS only version which is why I have plugin questions. It comes down to can you install plugins on the mail node and if so, what are you limited to or should be considered when setting a node up?

Thanks!
 

cPRex

Jurassic Moderator
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Hey there! I believe this section of our documentation will answer both of those questions, with the bold being my addition:

Code:
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.

You aren't able to access cPanel on the child node, so you might want to review the restrictions on the nodes here:

 

WebJIVE

Well-Known Member
Sep 30, 2007
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Thanks for the doc links. I'm still scratching my head on how SPAM would be handled?
 

WebJIVE

Well-Known Member
Sep 30, 2007
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68
The configuration changes happen on the parent in cPanel, but the spam processing happens on the child machine.
This creates quite a problem for handling SPAM with SPAMAssasign or ASSP or other then since you can't install SPAM software on nodes?
 

WebJIVE

Well-Known Member
Sep 30, 2007
122
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SpamAssassin still works as normal, although at this point you are correct that you wouldn't be able to install third-party tools.
So we have to use Spam Assassin until this gets opened up to plugins?