Unable to ping domain name without FQDN

domain-controllerdomain-name-systemping

The domain name consists of numbers only, example 300010100. If I try pinging the name only without FQDN, it responds back with a very odd IP address, 0.154.29.62 and giving transmit failed errors. If I add .local to the end of the name, 300010100.local, then it pings fine. My issue is I have a client that is trying to install MS Management Reporter 2012 and because it tries to use the name only instead of the FQDN and because the name only is unresovable, we cannot get the software to install. How can I get the number only to be able to ping correctly?

Best Answer

The issue is most likely that the number is being interpreted as the decimal equivalent of a dotted IP address. The easiest way to confirm is to open up the nslookup client and repeat your tests there. This is one of the reasons why purely numeric DNS labels are a bad idea; resolver libraries accept an input of IP addresses and DNS entities, and will tend to err in favor of passing IP address representations through unmodified. Only DNS focused tools such as nslookup and dig which bypass the resolver library and assume that the input should be interpreted as a name will be exempt from this.

Workaround: Use the fully qualified name. (300010100.contoso.com instead of 300010100) This forces the resolver to interpret the input as a DNS entity and avoids the undesired translation to IP address. If you find yourself in a bizarre scenario where 300010100 is the FQDN and there is no domain component, append a dot to the end. (300010100.) The terminating dot tells the resolver that this is a fully qualified name, and forces the integer to be interpreted as a name.

(Of note, my Windows 7 workstation translates 300010100 to 17.225.202.116 using the ping command, and I need a value of 10100030 to replicate your result of 0.154.29.62. Obfuscation in your question perhaps?)

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