41

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.

Braiam
  • 67,791
  • 32
  • 179
  • 269
mjazzy
  • 413
  • 1
  • 4
  • 4

4 Answers4

52

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.

Braiam
  • 67,791
  • 32
  • 179
  • 269
  • 3
    I 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) – MechMK1 Mar 04 '14 at 18:23
  • if this doesn't work try nmap -PN microsoft.com – whale_steward Mar 05 '14 at 01:14
  • @whale_steward my solution doesn't need to probe all ports with SYN packets, just the interesting one (80) – Braiam Mar 05 '14 at 01:16
  • @DavidStockinger that test uses the normal ICMP echo ping, and will be not useful in this case. If you deactivate the reverse DNS setting it will timeout and report the host is down, check with nmap -sn -n microsoft.com – Braiam Mar 05 '14 at 01:19
  • @Braiam, when i tried your solution it give Starting Nmap 5.21 ( http://nmap.org ) at 2014-03-05 08:35 WIB Hostname microsoft.com resolves to 2 IPs. Only scanned 64.4.11.37 Note: Host seems down. If it is really up, but blocking our ping probes, try -PN Nmap done: 1 IP address (0 hosts up) scanned in 3.25 seconds solution, the result is different with your post above, while using nmap -PN show the same result with additional port – whale_steward Mar 05 '14 at 01:38
  • @whale_steward what exactly you tried? Remember that my version of nmap is newer than yours. – Braiam Mar 05 '14 at 01:41
  • @Braiam this nmap -p 80 microsoft.com exactly as you write above, i don't know about new version (i update ubuntu package regularly), my version is Nmap version 5.21 ( http://nmap.org ) – whale_steward Mar 05 '14 at 02:27
  • @Braiam: Not true. I tried pinging, did not work. I tried nmap's -sn, it worked. – MechMK1 Mar 05 '14 at 07:14
  • 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, -sn will fail. Try with nmap -sn -n microsoft.com since it disables reverse DNS and you will see the result. – Braiam Mar 05 '14 at 17:47
  • 2
    Indeed, my fault. – MechMK1 Mar 05 '14 at 21:30
20

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.

Dan
  • 6,753
  • 5
  • 26
  • 43
  • 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 – Kellen Stuart Jan 05 '17 at 06:15
20

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
kamil
  • 7,355
  • 7
  • 40
  • 61
2

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.

enter image description here

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.

nux
  • 38,017
  • 35
  • 118
  • 131