What could cause a ping to fail if I am able to load the site's homepage in a browser?

Nick Pickering picture Nick Pickering · Dec 16, 2012 · Viewed 11.4k times · Source

I am able to load the website's homepage from a web browser, but pinging it from the command line is resulting in 100% loss from multiple machines.

I apologize if this is out of scope. Point me in the right direction and I'll take my question elsewhere.

The traceroute looks as follows (by random, I mean I don't recognize them):

Hop (ms)    (ms)    (ms)             IP Address Host name
1     3       0       0          __random.ip__   __random.host.net__  
2     4       0       0          __random.ip__   __random.host.net__  
3     0       0       0          __random.ip__   __random.host.net__  
4     20      20      20         __random.ip__   __random.host.net__  
5     20      20      21         __random.ip__   __random.host.net__  
6     28      28      28         __random.ip__   __random.host.net__  
7     32      32      31         __random.ip__   __random.host.net__  
8     Timed out       Timed out       Timed out               -  
9     Timed out       Timed out       Timed out               -  
10    Timed out       Timed out       Timed out               -  
11    Timed out       Timed out       Timed out               -  

Answer

Jonathon Reinhart picture Jonathon Reinhart · Dec 16, 2012

ping is a utility which sends an ICMP "echo request" message to a machine, who, if it is supported and enabled, will reply back with the same packet that was sent to it.

The website is being served by a webserver listening on TCP port 80.

These are two totally different services, and one, both, or neither could be enabled on any machine.

What you are probably seeing is that the machine you are connecting to has a webserver running, but has ICMP requests disabled. Also, any number of firewalls could exist between you and this box, any of which could be filtering out ICMP traffic.

In fact, recent versions of Windows disable ICMP ECHO in the default firewall rules. It has to be explicitly enabled.