Sorry, I should have quoted the errors more carefully. 

> I wonder why it says DHCP failed instead of no success with DHCP.

You are right, it does say "no success with DHCP". 

> If "0.0.0.0" is too short, the chances are "0.0.0.0/0" may be the valid form.

The exact error is "Invalid address length 4 - must be 6 bytes". I tried a few others including 0.0.0.0 but none of them worked. Not specifying this argument however doesn't trigger any complaints. 

Perhaps it's time to peruse the man pages for ip! But I have to put this down for now and will come back to it this weekend. 
------------------------------------------
9fans: 9fans
Permalink: https://9fans.topicbox.com/groups/9fans/T84b4492f91f2abb6-M6e8f58d18be9957c0e897fb1
Delivery options: https://9fans.topicbox.com/groups/9fans/subscription