DNS CNAME to mDNS .local

I can't for the life of me figure out why I can't get this to work. I feel like I've tried everything and am missing something simple.

I want foo.stonegray.ca to point to foo.local so that it will query mDNS. Simple enough, right? I figured this would be a great trick to get SSL certs for mDNS devices.

So I set up my DNS, and it seems to look ok to me when I dig it:

;; QUESTION SECTION: ;foo.stonegray.ca. IN A ;; ANSWER SECTION: foo.stonegray.ca. 300 IN CNAME foo.local. 

But no cigar.

ping: cannot resolve foo.stonegray.ca: Unknown host

The server itself works and resolves fine on the LAN:

sg:~ sg$ ping foo.local (172.17.x.x): 56 data bytes 64 bytes from 172.17.x.x: icmp_seq=0 ttl=64 time=0.070 ms 

I've tried multiple machines, networks, mDNS tools, sniffed with Wireshark (and nothing seems to send queries for foo.local from the cname)

Questions:

• Is this even supposed to work? I can't find anything that says I can't in RFCs; but there's no mention of anything .local related
• If not, any clue what I'm doing wrong or what I can test?