I want to manage remote libvirt , have run libvirtd in the dest host :

[root@dest_host ~]# ps aux | grep libvirtd 
root      3293  0.0  0.1 923796  5856 ?        Sl   12:59   0:00 libvirtd --daemon

then I use the command in source host :

 1.   [root@source_host ~]# ssh -l root 211.87.***.97             ## login the dest host
 2.   [root@dest_host ~]# virsh -c qemu+ssh://127.0.0.1/system list --all        # query vm status

output:
 Id    Name                           State
----------------------------------------------------
 -     ubuntu                         shut off
 -     vdisk                          shut off


also I use the command in source host 

  1.  [root@source_host ~]# ssh -l root 211.87.***.97    ## login the dest host
  2.  [root@dest_host ~]# virsh -c qemu+ssh://211.87.***.97/system list --all    ### query vm status

output:
 Id    Name                           State
----------------------------------------------------
 -     ubuntu                         shut off
 -     vdisk                          shut off



however ,   in the source host , execute the command :

   1. [root@source_host ~]# virsh -c qemu+ssh://211.87.228.97/system list --all    ### query vm status 

output:
error: failed to connect to the hypervisor
error: no valid connection
error: End of file while reading data: : Input/output error

I have referred to 
   http://wiki.libvirt.org/page/Failed_to_connect_to_the_hypervisor#Other_errors ,     
   http://wiki.libvirt.org/page/SSHSetup and 
   http://wiki.libvirt.org/page/SSHPolicyKitSetup . 
All of them don't work.

how should I do ? Help .