code: public static List<HostAddress> resolveXMPPServiceDomain(DnsName domain, List<HostAddress> failedAddresses, DnssecMode dnssecMode) {
          return resolveDomain(domain, DomainType.client, failedAddresses, dnssecMode);
      }
docs: Returns a list of HostAddresses under which the specified XMPP server can be reached at for client-to-server
  communication. A DNS lookup for a SRV record in the form "_xmpp-client._tcp.example.com" is attempted, according
  to section 3.2.1 of RFC 6120. If that lookup fails, it's assumed that the XMPP server lives at the host resolved
  by a DNS lookup at the specified domain on the default port of 5222.
  <p>
  As an example, a lookup for "example.com" may return "im.example.com:5269".
  </p>
  
  @param domain the domain.
  @param failedAddresses on optional list that will be populated with host addresses that failed to resolve.
  @param dnssecMode DNSSec mode.
  @return List of HostAddress, which encompasses the hostname and port that the
  XMPP server can be reached at for the specified domain.