Wednesday, November 11, 2015

Some Hands-On Cisco Troubleshooting Today

Today I got to put into practice at work some of the stuff I've been reading up on. I was configuring the integrated lights-out management ports on some HP DL360 servers, but could not access them over the network. The network engineer I work with gave me access to the Cisco 4948 switch that the servers are connected to, and I experimented with port speed and duplex settings to no avail.

I pulled up the running config and noticed that the VLAN trunk port from the switch back to the Juniper MX480 router we're using was misconfigured. The original port config looked like this in part:

interface TenGigabitEthernet1/49
 switchport trunk allowed vlan 100-103
 switchport mode trunk

It should have looked like this:

interface TenGigabitEthernet1/49
 switchport trunk allowed vlan 100-104
 switchport mode trunk

Difference in bold.

In other words, van 104, which carries the iLO traffic, wasn't being trunked back to the router, so it wasn't accessible from anywhere else on the network. As soon as I added vlan 104 to the trunk port I was able to ping the iLO ports from outside that vlan.

I have to say, I feel pretty good about myself for catching that.

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