code: protected void setServerName(String serverName) {
  
          if (CmsStringUtil.isEmpty(serverName) || (WILDCARD.equals(serverName))) {
              m_serverName = WILDCARD;
          } else {
              m_serverName = serverName.trim();
          }
      }
docs: Sets the hostname (e.g. localhost) which is required to access this site.<p>
  
  Setting the hostname to "*" is a wildcard that matches all hostnames
  
  @param serverName the hostname (e.g. localhost) which is required to access this site