DNS works in terminal but not elsewhere in Mac OS I have an issue similar to the one in this question: DNS not resolving on Mac OS.

Things out on the Internet work fine. Local machines in my company, however, fail to resolve, including the servers I'm trying to work on. 

We use local DNS servers and my Network preferences show only those local DNS servers. (192.168.20.10, 192.168.25.10)

Trying to get to them via hostname.companyname.local or hostname.companyname.com fails in mac OS apps (Safari, Firefox, Chrome, RDC, etc). However, if I use dig or nslookup in the terminal, it comes back just fine:

dig hostname.companyname.local

; &lt;&lt;&gt;&gt; DiG 9.8.3-P1 &lt;&lt;&gt;&gt; hostname.companyname.local
;; global options: +cmd
;; Got answer:
;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: NOERROR, id: 16841
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;hostname.companyname.local.        IN  A

;; ANSWER SECTION:
hostname.companyname.local. 1200    IN  A   192.168.25.24

;; Query time: 3 msec
;; SERVER: 192.168.20.10#53(192.168.20.10)
;; WHEN: Thu Nov 20 11:36:49 2014
;; MSG SIZE  rcvd: 54


So, why does it work in Terminal and why doesn't it work in Mac OS? (Using Yosemite.) The answer from the previously linked thread about bouncing mDNSResponder sounded promising, but that doesn't appear to exist in Yosemite.
Why does it work in Terminal and why doesn't it work in Mac OS? The answer to your first part is in man dig or man host:


  The dig command does not use the host name and address resolution or the DNS query routing mechanisms used by other processes running on Mac OS X.  The results of name or address queries printed by dig may differ from those found by other processes that use the Mac OS X native name and address resolution mechanisms.  The results of DNS queries may also differ from queries that use the Mac OS X DNS routing library.


To answer the second part, I would run a packet trace and see if the query packets are going out, and if so, to where? tcpdump -i en0 -vnnt "udp port 53"

mDNS is for Bonjour discovery; I don't believe it has much to do with standard DNS but don't quote me on that.