<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"> <META NAME="Generator" CONTENT="MS Exchange Server version 5.5.2653.12"> <TITLE>Question about host up/down</TITLE> </HEAD> <BODY> All, I have one server running at a colo I monitor from my office. I have services set for HTTP, SSH and FTP. It's host check is PING. This morning the colo had to temporarily block ICMP due to DDoS, though all my services were still up, it showed host down. I verified in Nagios, and all 3 services were still green, but the host was red. My understanding is that Nagios does not check the host unless a service fails, since I do not have PING as a service, what would cause this? Thanks in advance, Daniel Jimenez Systems Administrator </BODY> </HTML>