Hi,
I have windows server 2012 essentials setup and I'm using it for DNS since it handles all its necessary entries for easy domain joining and such. However, I'm using my router for DHCP, static assigning of IP addresses to some servers, and therefore the DNS entries for those servers; in addition I put those servers on the companyname.com domain so that demos and stuff show better URLs, but there are also externally hosted DNS entries that manage the rest of the companyname.com domain (i.e. our corporate site) so that its available externally. In addition the external DNS is through comcast business so technically those are assigned by their DHCP and could change. So, what I wanted to do is to have the windows server 2012 essentials handle the companyname.local domain, and then forward all other requests to the router which knows about the special internal companyname.com IP addresses, as well as the external comcast DNS servers. My understanding is that this should be accomplished with a DNS forwarder pointed at the router, which I have configured. My router at 192.168.1.1, the server is at 192.168.1.25, and clients are setup (through DHCP) to have their DNS server as 192.168.1.25 (the server).
The problem is that what appear to be random fqdns cannot be resolved by the server; i.e. lets say I have a server foo (.50) and bar (.51); foo will work on both
nslookup foo.companyname.com // => returns 192.168.1.50 nslookup foo.companyname.com 192.168.1.1 // => returns 192.168.1.50
However, bar won't work on the server, but will on the router
nslookup bar.companyname.com // => returns Non-existent domain nslookup bar.companyname.com 192.168.1.1 // => returns 192.168.1.51
I haven't found the exact way to get it to work, but if I restart the server, the query bar again from the server it will correctly return the forwarded request's answer. I'm not sure what's happening, although it seems like perhaps the router is sometimes responding slowly or the server is somehow not getting a response, and then its caching that forever. My questions are:
- How can I debug this further to figure out why the router replies with the DNS entry, but the server doesn't, even though it has a forwarded pointed at the router?
- 2) To test out whether its caching a bad DNS request for ever and ever, can I force the server to not cache any DNS requests and always forward items it doesn't know to the forwarder? Or perhaps more performant, just unknown entries? (although the router and server are close enough, the business is small enough, that I'm not concerned if every non companyname.local request had to travel to the router and back, and it will correctly cache the responses from comcast's DNS servers).
Thanks,
\Peter