code: protected String getUserIpLimits(Authentication auth) {
          Object principal = auth.getPrincipal();
  
          if (principal instanceof DuracloudUserDetails) {
              DuracloudUserDetails userDetails = (DuracloudUserDetails) principal;
              return userDetails.getIpLimits();
          } else {
              return null;
          }
      }
docs: Retrieves the ip limits defined for a given user
  
  @param auth Authentication where user details can be found
  @return user ip limits, or null if no limits are set