> I have been asked by management a few times about why some pings fail > when you ping things like google servers and core routers at the ISP. > The short answer I give is that things like that are too busy being > the Internet to respond to all the ping traffic that doesn't do > anything to enable them to be the Internet. Best advice is to consult > your routing tables or contact your ISP and have your ifstated ping > the far-end of your internet connection. Those systems are typically > less busy and have a higher expectation of answering all pings while > up.
ICMP ECHOREQ is about the lowest form of life out there on the intertubes. Some routers will pass it, some won't, and if a router is busy along the way it's the first thing that is dropped. I've had to answer that question many times over the years. My standard response has been "pings are not important in the grand scheme of things. If there is any congestion along the path, it may be discarded for the greater good." -- "The problem with quotes on the internet is that it's very hard to verify their authenticity." -- Abraham Lincoln
