getaddrinfo() returning a different name to what is specified in /etc/hosts

Solution Verified - Updated -


  • getaddrinfo() behaviour for AF_INET and AF_INET6 addresses changed as of Red Hat Enterprise Linux 6.5
  • Different hostname is returned by the getaddrinfo() function when using an updated glibc.
  • Name resolution for addresses in hosts file behaves differently in glibc-2.12-1.131 or later.
  • A host entry in /etc/hosts does not return the hostname I expect it to.
  • A hostname in /etc/hosts returns the FQDN instead of the shortname.


  • Red Hat Enterprise Linux 6 (all architectures)
  • The glibc package prior to glibc-2.12-1.131.el6 installed
  • This glibc package updated in Red Hat Enterprise Linux 6.5
  • Hostnames defined in /etc/hosts
  • Application which does lookups using getaddrinfo() type AF_INET or AF_INET6 lookups of those hostnames.

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