OVFTool cannot set property successfully

I want to set some properties to ovf files.

I use ovftool as bellow:

ovftool --prop:ip=10.32.23.123 --prop:dns=255.255.254.0

when this command has been executed without error showing, I still cannot see the property of ovf files.

Then I used ovftool myovffile.ovf

I still can not see the property I want to set.

what should I do?