I just installed Slackware 12.1 on a DELL PowerEdge 1300. It has a brand new USRobotics Gigabit Ethernet PCI Adapter 10/100/1000mbps. I put this in there just in case it was an hardware issue but I still get the same results.

This box is a central logging server running Nagios and pulling information from Windows XP PCs running NSClient.

On Nagios the host details show those PCs as being down sometimes, then up. 0% packet loss to 100%.

Any ideas?

What tests are used to determine "up" status? Wrt tolerance, what's the timeout for state change for those tests? Wrt granularity, at what interval are the tests run? Is there a pattern in up/down state changes? If you manually monitor one of these hosts for a prolonged period with equivalent commandline tools (Tcptraceroute, Hping?) does that support the idea of host or network connectivity problems? If you monitor the Nagios hosts for a prolonged period, does it show ethernet link state problems (ethtool, miidiag or equiv), network connectivity problems, Nagios process latency or other problems due to machine load?

this is a bit over my head.. as in, I'm not very familiar with the process of monitoring the hosts using the tools you mentioned or what WRT is.

How exactly would I be able to test for wrt tolerance and granularity?

Thank you in advance

I'll skip the explanation if you don't mind and suggest you manually run a continuous ping from the Nagios box and another machine to one of the troublesome machines. If errors occur it should be easier to determine what goes on where. TIA

I've noticed this when i boot up:

dnsmasq: failed to create listening socket: address already in use

when i did the continuous ping, at one point the hosts would come back up and internet would be accessible, then they would go down and of course internet would not work.

I hope somebody would be willing to jump in right now, because I don't think I am the right person to help you further. Please accept my apologies.

I appreciate the effort, I know its frustrating working with someone who doesn't have a clue.

As I look into it more I'm finding out more. I was trying to set this box up with a static ip and can't get that to work properly, so for now I'm using DHCP until I can figure it out on a spare pc.

thanks again unSpawn for your patience.

Just a guess.
Are you aware of tcp_window_scaling ? See:
http://lwn.net/Articles/92727/

So. Did this get fixed Dachy?