Resolution differences for getaddrinfo versus host/dig/delv
p.mayers at imperial.ac.uk
Wed Nov 18 12:19:57 UTC 2015
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:
This hostname is resolvable using "dig" & "host", but on Linux (glibc
2.20) the "ping", "telnet" and "nc" commands return "unknown host" or
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. 60 IN CNAME
wildcard-emeawest.um.outlook.com. 60 IN A 126.96.36.199
(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
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.
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