// check InetAddress related features of stack
Map<String, Map<String,InetAddressInfo>> inetAddressMap = createInetAddressMap(protocol_configs, protocols) ;
Collection<InetAddress> addrs=getAddresses(inetAddressMap);
StackType ip_version=Util.getIpStackType(); // 0 = n/a, 4 = IPv4, 6 = IPv6
if(!addrs.isEmpty()) {
// check that all user-supplied InetAddresses have a consistent version
StackType addr_versions=determineIpVersionFromAddresses(addrs);
if(ip_version == StackType.Unknown)
ip_version=addr_versions;
else {
if(addr_versions != ip_version) { // mismatch between user supplied addresses and type of stack