Tip: Ping doesn’t work? Try "ping -4"

Today's post is about the famous "ping" command available in many operating systems. What the Windows ping command actually does is send an ICMP (Internet Control Message Protocol) Echo Request packet (packet type 8) to the given destination host.

However, nowadays IPv6 is here, and thus there's also ICMPv6 protocol in addition to the "original" ICMPv4 protocol used by default in many networks. For example, if you take a Windows 7 machine and simply try to ping your domain controller (for example), you might well receive the message "Destination host unreachable" or something similar.

However, it still might be that pings are in fact enabled on your network. If this is the case, it is time to instruct Windows 7's ping command to use ICMPv4 protocol instead. This can be done with the "-4" parameter, for example like this:

ping -4 myhostname

This might well work out, so be sure to try both the ICMPv6 and ICMPv4 versions. Remember that when you configure firewall settings, you also need to enable both versions.