Mac OS X: Do Not Use Leading Zeros in IP Address

Mac OS X and Mac OS X Server treats IP addresses with leading zeros as if they were octal numbers. Therefore, do not use leading zeros when setting up the Mac OS X Server IP address through Network Preferences.
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Symptom

A Mac OS X or Mac OS X Server computer cannot make a network connection. Additionally, the IP address shown in Network Preferences is different than the address originally entered.

Product affected
  • Mac OS X
  • Mac OS X Server

Solution

Do not use leading zeros when setting up a Mac OS X or Mac OS X Server IP address in Network Preferences.

If an IP address is entered with leading zeros, Mac OS X interprets and converts the numbers to octal form rather than decimal form. For example, an IP address entered as 010.011.012.013 is converted by Mac OS X to 8.9.10.11 rather than 10.11.12.13.
Published Date: Oct 10, 2016