1. Overview
cPanel Linked Nodes allow two or more servers to connect through WHM’s Link Server Nodes interface. This architecture lets you offload specific services—such as mail—to dedicated child nodes, reducing load on the primary (parent) node and improving performance for web hosting and other services.
2. Server Profiles
You can optimize child nodes by assigning a server profile in WHM’s Server Profile interface. Profiles tailor the server for specific workloads.
Important: The parent node can only use the Standard profile.
3. Parent and Child Nodes
Linking nodes creates a parent–child relationship:
- Parent Node: The authoritative controller that assigns tasks to child nodes.
- Child Node: A non‑authoritative node that handles specific services such as mail.
The parent node also manages AutoSSL certificates for all child nodes.
4. Child Node Restrictions
Child nodes have several limitations:
- cPanel users cannot log in directly to a child node.
- Child and parent must share the same major cPanel version.
- All API calls must be made to the parent node; the parent proxies them to the child.
- cPanel API calls are blocked on the child node.
- WHM API calls that target distributed accounts are blocked on the child node.
- Each cPanel account can use only one child node per offloaded service.
- Multiple parent nodes cannot link to the same child node.
Mail Child Node Restrictions
- Users must log in to Webmail via
webmail.example.com, not port 2096. - Mail and Webmail subdomains resolve to the child node.
- IPv6 cannot be enabled for accounts distributed to a mail node.
- API Tokens must be enabled for the distributed account.
- DNS DCV is required for AutoSSL.
- Nodes must be able to manage the authoritative DNS server.
5. User Access and Security
Distributed accounts have the same level of access on the child node as on the parent node. This ensures compatibility but does not provide additional security.
For example, the Pipe to a Program option in Forwarders is disabled on distributed mail accounts. Users may still manually create such forwarders, but this functionality will not be preserved in future versions.
6. Distributed cPanel Accounts
A distributed account is one whose specific services (such as mail) are offloaded to a child node. The system creates two versions of the account:
- One on the parent node (main account)
- One on the child node (service‑specific account)
Important: AutoSSL for distributed accounts requires DNS DCV.
7. Creating Distributed Accounts
When creating a new account in WHM’s Create a New Account interface, you can assign a child node for mail using the Mail Routing section.
8. Converting Existing Accounts
To distribute an existing account, use the Modify an Account interface. The system will:
- Create the account on the child node
- Move the selected services (e.g., mail) to the child node
- Remove the old mail data from the parent node after migration
9. Mail Behavior on Linked Nodes
Most IMAP, POP3, and SMTP traffic goes directly to the mail child node. If traffic reaches the parent node due to cached DNS, the parent will:
- Proxy IMAP/POP3 connections to the child node
- Reroute SMTP delivery to the child node
Warning: Email forwarders that pipe to programs are not supported on distributed mail nodes.
10. Managing Distributed Accounts
Only system administrators can manage distributed accounts. You can:
- View distributed accounts in WHM’s
Link Server Nodesinterface - Modify distribution settings
- Undo distribution (dedistribute)
11. Undoing Distribution (Dedistribution)
Dedistribution moves services back from the child node to the parent node. During this process, the system:
- Reconfigures service proxying
- Updates mail routing
- Terminates IMAP/POP3 sessions
Conclusion
cPanel Linked Nodes provide a powerful way to scale hosting environments by offloading resource‑intensive services to dedicated child nodes. Understanding the restrictions, behavior, and management workflow ensures smooth operation and optimal performance across distributed accounts.