I can not ping microsoft.com but can open it through Firefox. I am using 12.04LTS. I am able to ping all other websites.
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4 Answers
In this particular case, microsoft servers blocks/drops ICMP packets and don't reply to them at all. For such cases is better use other tools like nmap to have an accurate result:
nmap -p 80 microsoft.com
Starting Nmap 6.40 ( http://nmap.org ) at 2014-03-03 13:08 AST
Nmap scan report for microsoft.com (65.55.58.201)
Host is up (0.14s latency).
Other addresses for microsoft.com (not scanned): 64.4.11.37
rDNS record for 65.55.58.201: 00001001.ch
PORT STATE SERVICE
80/tcp open http
Nmap done: 1 IP address (1 host up) scanned in 0.65 seconds
As you can see the "host is up" even through it doesn't answer the ICMP echo packet.
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3I suggest using
nmap -sn microsoft.com. It only checks if the host is online and does not scan any ports (which could be theoretically detected as "hack attempt" by some ISP's)– MechMK1Commented Mar 4, 2014 at 18:23 -
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@whale_steward my solution doesn't need to probe all ports with SYN packets, just the interesting one (80)– BraiamCommented Mar 5, 2014 at 1:16
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2@DavidStockinger as I said before, you are not pinging the host but doing a reverse DNS search, if you try against a system that blocks pings and has not DNS entries,
-snwill fail. Try withnmap -sn -n microsoft.comsince it disables reverse DNS and you will see the result.– BraiamCommented Mar 5, 2014 at 17:47 -
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I am unable to ping microsoft.com as well. This does not indicate any sort of problem. Many servers block this sort of traffic out of security or performance concerns. amazon.com similarly does not respond to pings.
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One important detail you missed is microsoft.com is not responding to ICMP which is a different protocol than http / https. On a web server, you can determine what services you want to listen to on a specified port. This is an important distinction to make for this question Commented Jan 5, 2017 at 6:15
Being Unable to ping a domain on the internet does not mean that the domain is down.
Ping is based on ICMP protocol and some domains stop receiving ICMP pings in their firewall to prevent some kind of SYN attacks (hacking technique)
So You should not use ping to see if a website is up or down. Instead, use telnet for websites on port 80
telnet microsoft.com 80
or use host to detect IPs/namserver
host microsoft.com
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Here i will show you how Microsoft.com block ICMP requests .
ICMP means Internet Control Message Protocol , echo request and echo response are the two operation codes of ICMP used to implement ping .
Bad ICMP packets are used for attacks such as :
Ping of death
ICMP flood attack
ICMP nuke attack
So Microsoft protect there Network by blocking ping_ICMP ana Traceroute_ICMP , so attackers want use it to exploit there system or know information about there network.
The Tracoute using ICMP (-I) option , shows that routers of microsoft block it and you can see asterisks , and blocking these ICMP packets , disable the ability to ping microsoft.com.
