Configuring PPmac Nameserver and Default IP Gateway

The PPmac reaches devices by IP address but fails when a hostname is used, or it reaches the local subnet but cannot communicate through a router. Configure the nameserver from a Telnet session and configure the gateway through the PowerPMAC IDE. Treat these as separate settings: DNS translates hostnames into IP addresses, while the gateway routes traffic beyond the controller's local subnet.

Symptom and Configuration Path

Before anything else, confirm which communication function has failed. Testing the wrong layer can make a correct gateway look like a DNS fault or a correct nameserver look like a routing fault.

Use a direct IP-address test first. If the target IP is reachable but its hostname is not, repair the nameserver configuration. If a local IP is reachable but a remote IP is not, inspect the gateway. If local IP communication also fails, stop and correct the local interface or network connection first.

DNS and Gateway Mechanisms

A nameserver does not carry application traffic. It answers a lookup request by returning an IP address for a hostname. The PPmac then opens the actual connection to that returned address. A missing or incorrect nameserver line therefore breaks hostname-based connections while direct IP connections may continue to work.

The default gateway performs a different job. The controller compares a destination address with its own subnet. It sends local destinations directly on the local network; it sends destinations outside that subnet to the configured gateway. An incorrect gateway can leave local communication fully operational while blocking remote networks.

DNS may depend on the gateway when the nameserver itself is outside the local subnet. In that case, an accurate nameserver entry still fails until routing to that server works. Diagnose in this order: local IP communication, off-subnet IP communication when required, and hostname resolution last.

Nameserver Configuration by Telnet

Changing the nameserver requires a Telnet session, a temporary read-write remount of the root filesystem, an edit to resolv.conf, restoration of read-only mode, and a PPmac reboot. Have the approved nameserver IP address available before opening the session.

1. Connect to the PPmac through Telnet and change to the configuration directory:

   cd /.readonly/etc

   Confirm that the working directory is /.readonly/etc. Do not move on until the path is correct; editing a similarly named file elsewhere will not apply the intended persistent setting.

2. Remount the root filesystem read-write:

   mount -o remount,rw /

   Confirm that the command completes without an error before attempting the edit.

3. Create or edit resolv.conf with the editor available on the controller. Add a line in this form:

   nameserver {ip}

   Replace {ip} with the actual nameserver address; do not type the braces. The supplied configuration example is:

   nameserver 10.10.98.7

   Read the saved file back and confirm the keyword is spelled nameserver, the address is correct, and the entry is not commented out.

4. Return the root filesystem to read-only mode:

   mount -o remount,ro /

   Do not move on until the remount completes without an error. Leaving the filesystem writable increases exposure to unintended configuration changes.

5. Reboot the PPmac. The reboot is part of the configuration procedure, so plan for the resulting controller and communications interruption.

Gateway Configuration in the PowerPMAC IDE

Use the IDE for the gateway rather than editing unrelated network files through Telnet. Obtain the gateway address from the approved network design and confirm that it belongs to the controller's intended local network.

1. Connect the PowerPMAC IDE to the intended controller. Confirm the controller identity and current IP configuration before changing any network value.

2. Open Tools > Options.

3. Select PowerPMAC > IP Address Change Setup. Confirm that the displayed settings belong to the same PPmac reached in the first step.

4. Enter the required gateway in the gateway field. Recheck every address octet before applying the change; a typing error can preserve local access while removing access from routed engineering networks.

5. Apply the configuration using the IDE controls. If the IDE requests a restart or reconnection, complete it and reconnect using the active controller address.

Changing the gateway does not repair a wrong nameserver entry. Likewise, editing resolv.conf does not create a route to remote subnets. Configure both only when the network design requires both services.

Commissioning Checks and Recurring Pitfalls

1. Test a known device on the PPmac local subnet by IP address. Do not continue until local addressing and the physical link work.

2. If routed communication is required, test a known off-subnet destination by IP address. Success confirms that the gateway path works independently of DNS.

3. Test the same required service by hostname. Success confirms that name resolution and the subsequent routed connection both work.

4. After rebooting, reconnect and read /.readonly/etc/resolv.conf. Confirm that the intended nameserver line remains present.

5. Repeat the off-subnet IP and hostname tests after the reboot. This distinguishes a saved configuration from a change that worked only during the initial session.

Frequently Asked Questions