check SNMP Cisco switch link errors

Project Notes

This simple script is written in Bash and should be quite clear to read and hack, I think.

There are other Perl scripts around, but if you don't know Perl or regular expressions and like to hack things your way, this might be something for you.
(It's a bit slow though on a 72 ports C3750.)

command line:

check_cisco_snmp_link_errors [hostname]

or

check_cisco_snmp_link_errors [hostname] [readcommunity] [in_error_threshold_per_day] [in_error_treshold_max] [out_error_treshold_max]

Basically the output tells you if the errors on the ethernet interfaces of your Cisco switch have exceeded a certain treshold.
The current default treshold is 4 errors/day (using uptime) for incoming packets (so no need to reset the counters) with the upper limit of 500 errors in total and 1 error in total for outgoing packets per interface (in general, should not occur).
If you'd like per link interface trends, you can better obtain that using SNMP from the monitored hosts itself or use Cricket. This is just to see the general status of your switch. The culprit(s) is/are outputted together with link name and if available, the link description.

Currently only tested on C3750, C2900 and C2950XL's