Hi there, I was evaluating nagios and found a strange behavior on my test setup. After a fresh install, I did a minimal setup, just one contactgroup with one contact. A hostgroup with 4 hosts (no parent relationship). Since I´m only interested to know if a host is up or down I just configured a check_ping service for each host. As I said, a pretty simple setup. The services is schedulled to run every minute with a one try only. To simulate a network problem, I just did a "iptables -A INPUT -p icmp -j DROP". I was expecting that I would see all hosts/services down within a minute, as nagios use to "spread" the checks within the one minute (default configuration). To my suprise I saw just one host coming down on one minute, with the subsequent hosts coming down each minute after that. I mean, host 1 comes down on, say, 8:40:13, host 2 on 8:41:05, host 3 on 8:42:05 and host 5 on host 8:43:05. I saw the last host come down almost 4 minutes after the "network problem". My first try was with nagios 1.3, but the I could reproduce the same problem with nagios 2.1. When I asked a friend to do the same test, he got the same results. A little worst, since he does not check the hosts/services every minute, so he got a host down per 3 minutes, after 10 minutes he couldnt see all the hosts down. To my surprise, all the hosts come up about the same time after removing the iptables rule. I could not find a explanation for this behavior, and couldnt find anything wrong with the configuration. I´m not sure if this is a feature, or if I hit a bug. A serious bug to be true. I did a minimal search on the mailing list archives and forums, so excuse me if this is know issue, and plz point me where I can find more about it. Christian Lyra