Israel Brewster wrote: > I am showing some odd behavior with the check_icmp plugin. I am using > it to monitor a number of stations around the state, and for the most > part it appears to be working properly. However, with four of these > stations, check_icmp is showing consistently 60% loss-even though the > check_ping plugin shows them as fine, and just running a straight > ping on these sites also shows no packet loss. The only difference > between these sites and other sites we are monitoring is that they > are running linksys RV082 routers, while other sites are running > different model linksys routers. Would anyone be able to explain why > I am seeing this sort of behavior? Thanks. >
Perhaps I can shed some light on this. check_icmp is designed to spew out packets very rapidly, while at the same time trying to be polite to the target it's checking. It does this by the simple expedient of waiting a, by default, very short maximum time between two packets which gets even shorter if the targeted host happens to answer to one of the probes being directed at it. When the targeted host *does* answer, check_icmp decides it can shorten the default interval and immediately send another probe, as the host it's targeting apparently isn't suffering from congestion. For *most* operating systems, this works quite nicely, and check_icmp is capable of deciding the latency and loss very quickly. Other operating systems thinks check_icmp sends packets too quickly and drops a few of the probes. That's probably what you're seeing. The way around it is to add the '-i' option with a suitable value, such as 0.3s, which will force a minimum interval of 0.3 seconds between each packet. Good luck -- Andreas Ericsson [EMAIL PROTECTED] OP5 AB www.op5.se Tel: +46 8-230225 Fax: +46 8-230231 ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Nagios-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
