code: public String firstCalledName() {
  
          calledName = hostName.name;
  
          if( Character.isDigit( calledName.charAt( 0 ))) {
              int i, len, dots;
              char[] data;
  
              i = dots = 0;                    /* quick IP address validation */
              len = calledName.length();
              data = calledName.toCharArray();
              while( i < len && Character.isDigit( data[i++] )) {
                  if( i == len && dots == 3 ) {
                      // probably an IP address
                      calledName = SMBSERVER_NAME;
                      break;
                  }
                  if( i < len && data[i] == '.' ) {
                      dots++;
                      i++;
                  }
              }
          } else {
              switch (hostName.hexCode) {
                  case 0x1B:
                  case 0x1C:
                  case 0x1D:
                      calledName = SMBSERVER_NAME;
              }
          }
  
          return calledName;
      }
docs: /* Guess next called name to try for session establishment. These
  methods are used by the smb package.