Comment 7 for bug 886509

I re-prioritized this task because this will require some feedback from the HIP WG and Xin is going to send email about this. The dual support in hipd and DNS proxy actually a bit more complicated than I originally thought; either we need a "flag day" for HIPv2 or we need to modify the specifications for smoother transition to HIPv2 (or in the future, HIPv3). The TCP client support can developed independently of this.