MacOS – OSX Yosemite DNS cache Issues

Hostname resolution in Mac OS X (since ~10.3) has roughly spoken - i exclude various cache mechanisms - the following operating sequence:

1. 'Files' (e.g. /etc/hosts) ->
2. mDNS ->
3. DNS (search domains) ->
4. DNS

Valid names for the different name resolution methods:

for 1: almost arbitrary names
for 2: name.local
for 3: name (+ search.domain in your network prefs) A Start Of Authority (SOA) record for the top level domain is obligatory.
for 4: fqdn

In your first scenario (myserver.local) you only use 'Files' and mDNS. 'Files' fails because there is no entry myserver.local in your hosts file. mDNS succeeds resolving it because it's a valid and resolvable mDNS name.

In your second scenario (myserver & search.domain local) you use 1, 2, 3 (and 4). 'Files' fails because you have no entry myserver, mDNS fails because it's no valid mDNS name. DNS (search domains) fails because you don't have a DNS-server with a SOA record for .local in your network (as well as DNS).

So just enter sudo nano /etc/hosts in Terminal and add the line:

 a.x.y.z      myserver

(a.x.y.z= IP-number of your server) and it should work. If you are really lazy even an 'a' as name might be sufficient. But don't use single numbers (like 1 or 123) because then ssh might try to connect to 0.0.0.1 or 0.0.0.123. At least ping connects to 0.0.0.1 or 0.0.0.123.

Apple uses .local for bonjour.

This is reserved for mDNS in RFC 6762.

You should not use this in a mixed network. See https://en.wikipedia.org/wiki/.local for further discussion.