I just set up an internal http server for internal use (I set up Redmine), in a small network (30 or so PCs).
I set up the http server on a virtual box ubuntu, that runs also the DNS server (bind). In the DNS lookup I added the Redmine server name (redmine.engserver <-> 192.168.1.14) and as forwarders the outside ISP DNS IP adresses.
I am using a small wi-fi router (ASUS RT-N66U) as DHCP (and as gateway). In the DHCP config page I set up as DNS the ubuntu server IP (it is fixed 192.168.1.14). Now when I connect a new PC to the network, the DHCP router issues its new IP and as DNS servers it issues: primary: 192.168.1.14 (ubuntu machine) and seconary 192.168.1.1 (the router itself).
ipconfig /all Default Gateway . . . . . . . . . : 192.168.1.1 DHCP Server . . . . . . . . . . . : 192.168.1.1 DHCPv6 IAID . . . . . . . . . . . : 248539109 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-15-AA-3F-D0-67-E5-49-A7-EF
DNS Servers . . . . . . . . . . . : 192.168.1.14 192.168.1.1 NetBIOS over Tcpip. . . . . . . . : Enabled
Before changing the DHCP setting on the router, I would always get only one DNS server: 192.168.1.1 (which uses probably DNS forwarding to external public DNS services).
The problem is this: If in my browser I type www.google.com, it works all the time. If in the browser I type http://redmine.engserver/ it works most of the time, but sometimes it ends up with a yahoo page search or something else. In the DNS cache it shows as (Server not found). ipconfig /displaydns
I looked with wireshark and it seems like sometimes the client PC interrogates the secondary DNS (192.168.1.1) instead of the first 192.168.1.14. Obviously this one is a public domain and it does not have the redmine.engserver entry.
What is wrong in this configuration? Is it even legitimate to have 2 DNS (one internal and one forwarded by the router) which are inconsistent? Is there another way to have a local name service in a small office network? Why is the router DHCP issuing itself as DNS?