Resolution differences for getaddrinfo versus host/dig/delv

[Phil Mayers]

All,

This isn't strictly a "bind" question, but it kind-of, sort-of is.

We've got an Office 365 tenancy, along with offsite voicemail. We send 
our SIP connections to a hostname:

$GUID.um.outlook.com

This hostname is resolvable using "dig" & "host", but on Linux (glibc 
2.20) the "ping", "telnet" and "nc" commands return "unknown host" or 
equivalent.

I suspect getaddrinfo isn't parsing the DNS response for some reason.

Can anyone cast their eye over the response to the query below and guess 
why host/dig/delv think it's OK, but glibc getaddrinfo() apparently doesn't?

$ dig blahblah.um.outlook.com

;; ANSWER SECTION:
blahblah.um.outlook.com. 118	IN	CNAME 
*.um.outlook.com.glbdns2.microsoft.com.
*.um.outlook.com.glbdns2.microsoft.com.	60 IN CNAME 
wildcard-emeawest.um.outlook.com.
wildcard-emeawest.um.outlook.com. 60 IN	A	157.55.9.252

(It's a wildcard, any left-hand-side will work)

Obviously the *.thing on the RHS of the first CNAME is weird, but is it 
illegal?

If you're of a sensitive disposition I'd avoid digging (pardon the pun) 
into the minutiae of the zone surrounding those records e.g. enclosing 
SOA - they're very seriously odd.

Cheers,
Phil