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I wonder why my server(s) don't respond to ping?

Check this one: klusteranalytics.com

$ ping klusteranalytics.com
PING klusteranalytics.com (50.17.214.205): 56 data bytes
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
Request timeout for icmp_seq 2

But it does resolve:

$ curl -i -X HEAD http://klusteranalytics.com
HTTP/1.1 200 OK
Server: nginx/0.8.54
Date: Tue, 29 Mar 2011 05:07:43 GMT
Content-Type: text/html
Content-Length: 2527
Last-Modified: Fri, 04 Feb 2011 18:19:57 GMT
Connection: keep-alive
Accept-Ranges: bytes
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2 Answers

up vote 5 down vote accepted

Because somewhere between you and your web server, they're blocking ICMP traffic.

Or because your host really is offline.

ping is not a suitable method of checking if your site is alive. When I run telnet klusteranalytics.com 80 I get the expected HTTP response, so it's safe to assume that somewhere ICMP packets are being dropped. This is not unusual, but is kinda pointless for a web host.

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Thanks! The default EC2 security groups is not configured for that, another developer thought that was an issue (since he wasn't able to connect to a service). – igorgue Mar 29 '11 at 6:10
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up vote -5 down vote

Because DOMAINS NEVER RESPOND TO PING. Only servers can.

And in your case quite oviously the server is configured not to responst to ICMP messages (which is what a ping is). Or an element in between (a router or firewall) throws it away.

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Thanks, your answer is correct too, but I picked the kind one with no UPPERCASE message ;-) – igorgue Mar 29 '11 at 6:11
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No need to yell. – John Gardeniers Mar 29 '11 at 6:39
This is also technically incorrect. Presumably the domain resolves to an IP address, which is present on a server and may ping. – JamesHannah Mar 29 '11 at 7:27
JamesHannah - he's rude but he's right, and he explains your point of view, too rude though. – Chopper3 Mar 30 '11 at 8:39
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