I have set up an ERL at home with 4 VLANs configured and a zone-based firewall.
I run a 'Split-Horizon' DNS system so that when I'm at home, my mobile devices connect to network services like my mail server using the internal connection, and when I'm away, the same URLs will connect to the same services, assuming the firewall and port forwarding is enabled.
As an example, if I want to SSH into my ERL at home or away, I'd simply type:
ssh [user]@edgerouter.[mydomain]
This worked great when I was running a BIND instance at home, but ever since moving to the ERL and its static-hosts approach (which is a great system when it works), my MacOS computers tend to resove DNS names to the external IP address after a while.
Issueing the following command works for a short while, but after a few minutes, the external IP is again used:
sudo dscacheutil -flushcache;sudo killall -HUP mDNSResponder
Strangely, ns-lookup and dig commands always return the correct internal IP address, but Chrome, Safari, SSH, VNC etc. all don't have such a consistent result.
I have a feeling this is more likely to be a MacOS thing, but it's pretty consistent on both El Capitan and Yosemite.
Anyone have any ideas?