[Nagiosplug-devel] more info on network management plugins

Subhendu Ghosh sghosh at sghosh.org
Wed Sep 11 12:04:58 CEST 2002

Sorry - don't mean to be nit-picking...


On 11 Sep 2002, Guy Van Den Bergh wrote:

> Hi there,
> It took a while, but here is some more info on the network management
> plugins I submitted to the list about a week ago.
> 1. What has check_xinterface to offer over check_ifoperstatus.pl?
> (I have developed check_xinterface because check_ifoperstatus didn't
> really do what I wanted.)
> *) check_xinterface considers also the administrative status of the
> interface: when the interface is admin down, only a WARNING status is
> returned (CRITICAL when admin up & operational down).

Is this logical? - often we have interfaces installed on devices that are
not in use and therefore admin down.  If monitoring a specific interface 
(therefore assumption is that it should be up), why would the interface go 
admin down - (if maintenance then scheduling downtime ...)

Inadvertent change of admin to down should get flagged on your
configuration diffs (You are doing those, right :)

> *) check_xinterface needs the ifIndex as well as the ifName as input
> options. This offers a method to detect when interface indices have
> changed, e.g. after a reboot (recent Cisco IOS versions support ifIndex
> persistence, but this is not always available; I do not know what a
> Juniper router does with the indices after a reboot).

By requiring both ifIndex and ifName in the config file you are forcing a 
nms reconfig because of a router reboot with snmp reindexing. Seems to me 
to be at cross-purposes in trying to maintain nms uptime.  

The current version of check_ifoperstatus supports either ifIndex or 
ifDescr for the interface.  It could be improved to use ifName instead of 
ifDescr if the -I (support for ifXTable) is provided.

> *) check_xinterface returns UNKNOWN when the snmp poll fails
> (check_ifoperstatus returns critical). SNMP implementations on
> commercial routers are pretty stable. Most of the time an SNMP poll
> failure means the router is down, and this is detected with the
> check-host-alive command.

True - but having a critical here allows for faster notification rather 
than waiting for the host-check max-attempts to expire.

> 2. The router environment plugins.
> It is indeed a good idea to fold both check_cisco_env and
> check_juniper_env into a single plugin, but I will need some more time
> to implement this. This way it should be easily extensible with other
> proprietary environment MIBs (Foundry, Unisphere, Alcatel, ...)

I can give you a hand on this, if you'd like.



More information about the Devel mailing list