Cisco Catalyst Configuration Using Cluster Commands

Posted on in Networking

If you work on a fairly spread out network (or have remote clients), you might be managing Cisco Catalyst switches that are far, far away. For a long time, I thought the only option was to have someone on site to pre-configure the switch just enough to get it on the network and accessible. Then I'd log in and finalize the configuration. Unfortunately, this method usually resulted in at least one problem. Now, I use the cluster commands to remotely configure Catalysts without on-site assistance.

The key to making this work is having DHCP running and an existing Catalyst switch you can access remotely. DHCP is a pretty common protocol on networks, so this shouldn't be a major issue. If there aren't any other Catalyst switches already on the network, you'll have to configure things the old way. (It occurs to me that this is a bit of a chicken-and-the-egg type problem.)

When you plug the brand new switch into the network, it will acquire an IP address via DHCP, by default. From there, this command list should finish the job.

  1. Log in to one of the other Catalyst switches already running on the network.
  2. show cdp neighbors (Optional) - If CDP is running and you've chosen to start from a switch that is connected to the new switch, you should see a neighbor named "Switch". This isn't really a necessary step, but it's useful to know things are working.
  3. cluster enable WORD - The cluster commands require you to be in configuration mode. You must give the cluster a name.
  4. show cluster candidates - Get out of configuration mode (or prefix this command with do) and see if you can see the new switch as a cluster member candidate. Remember it should be called "Switch".
  5. cluster member mac-address H.H.H - Back in configuration mode, this will add the new switch as a member of this cluster. The mac-address should be part of the information shown in the previous step.
  6. show cluster members (Optional) - Exit out of configuration mode. This command should list the command switch (the one you are on), and a member switch. The member switch is the device you are planning to configure and should be designated as member 1.
  7. rcommand 1 - This will log you into the new switch. You shouldn't need a password.
  8. Configure the the new switch.
  9. no cluster member 1 - Log off the new (and now configured) switch and remove it from the cluster. This step may not be really necessary, but better safe than sorry. It will remove the new switch from the temporary cluster.
  10. no cluster enable - This will remove the cluster and end the process.

At this point, you should be able to <acronym title="Secure Shell">SSH</acronym> or telnet into the new switch. The mistake I've made most often at this point is forgetting to set an enable password. Without both login (whether telnet or AAA) and enable passwords, the switch won't let you in.

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