So far in this series of blogs ( Basics, Tools and SNMP) I didn’t get vendor specific, the methods were applicable to any SNMP compliant network. In the next few entries it’s going to be Cisco specific, based on the well known IOS command line interface. The first command one should execute is the ‘show version’ command, not because the version is that important (it is but we are not going there this time), it’s because the show version can show us how long the device is up and running and what was the last reason it booted. Depending on the device and version you are running the command on, the lines you are looking for will usually appear in the third paragraph and are highlighted in bold:
SW3560#sh ver Cisco IOS Software, C3560 Software (C3560-IPBASEK9-M), Version 12.2(35)SE5, RELEASE SOFTWARE (fc1) Copyright (c) 1986-2007 by Cisco Systems, Inc. Compiled Fri 20-Jul-07 01:44 by nachen Image text-base: 0x00003000, data-base: 0x01300000 ROM: Bootstrap program is C3560 boot loader BOOTLDR: C3560 Boot Loader (C3560-HBOOT-M) Version 12.2(25r)SEC, RELEASE SOFTWARE (fc4) SW3560 uptime is 17 weeks, 1 day, 22 hours, 25 minutes System returned to ROM by power-on System restarted at 10:42:11 PDT Thu Oct 2 2008 System image file is “flash:c3560-ipbasek9-mz.122-35.SE5/c3560-ipbasek9-mz.122-35.SE5.bin”
What we can learn here is that this switch has been up (uptime) for 17 weeks, 1 day at least, which is a good indication of a stable system. Anything less then a week should be further examined as to the reason this switch has rebooted. The reason is indicated in the second highlighted line, in this case it was powered on (an indication of power outage, unless someone unplugged the power cord intentionally. Other reason is a reload command typed by a user and indicated by the ‘restarted by reload’ output. Besides that there are many other reasons to a software cycle, non of them is something you should see, if any of them is identified, the first step should be an upgrade, as indicated in the following links: http://www.cisco.com/en/US/products/hw/iad/ps397/products_tech_note09186a00800b4447.shtml http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_tech_note09186a008010876d.shtml There are many other commands, times up for now so it will have to wait for the next entry …
