Generally speaking, you should be pretty darn safe querying production systems using SNMP, as long as you only 'get' using the read-only community string, and avoid 'set'ting anything using read-write or read-write-all community string.   I suppose that if you tried really hard, you might be able to crash your access router, but I'm happily cluefree on possible details.

If you want a head start with your SNMP perlings, there are several working examples in the Networking Code section of Code Catacombs.   I'm reasonably happy with some of my own code there: "(code) Net::SNMP, Bandwidth, GnuPlot, PNG, PostScript, Excel" and "(code) Net::SNMP, table-ish interface stats" plus "Cisco SNMP CDP Poll" as well as "(code) mind your snmPs & Qs".
    cheers,
    Don
    striving toward Perl Adept
    (it's pronounced "why-bick")

Update: here's a few URLs that may be of interest:

In reply to Re: SNMP... Cisco AS5400... (SNMP is pretty safe) by ybiC
in thread SNMP for call info from a Cisco AS5400 Call Collector by enigmae

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