getnetbyaddr

getnetbyaddr address, [addrtype]

• Retrieves the network name or names of the given network address. (addrtype indicates the type of address. Often this function is used for IP addresses, where the type is not needed.) The return value in list context is:
  
  

  ($name, $aliases, $addrtype, $net)
  

  
  
  In scalar context, getnetbyaddr returns only the network name.