Our company has a guest wireless network for auditors, contractors, etc. to use when onsite. This wireless is meant to be an external only network, so it only touches the wireless controller, and a DNS server. The DNS server is only meant to provide the IP of the capture page on the WLC. After that, all DNS requests get forwarded to OpenDNS
Traffic flows like such: Client->DHCP->Wireless Controller(WLC)->Capture Page-> DNS-> WLC ->MPLS.
Our WLC is a Cisco 5510, which cannot host its own DHCP. The capture page works by redirecting any traffic to the DNS hostname specified on the controller, and then requiring credentials.
The issue we are running into is DNS requests failing. All active domain machines seem to work fine (keep in mind that this DNS server is not apart of our domain). Our auditors came in today to try and connect, but the DNS request was failing. When attempting to get an IP from nslookup, I received a "non-existent domain" error.
To try and replicate, I got a fresh load of windows, no domain affiliation, and attempted to connect to this network. I received no errors, and the DNS request worked fine. To further troubleshoot, i added a domain suffix to the NIC and checked the box to ensure it appended that suffix to DNS requests. Unexpectedly, that was still working.
Based on what troubleshooting I did on the auditors machine, I believe the DNS request from the wireless controller uses no suffix. this is because:
Requests to "WLC" fail with the non-existent domain error.
Requests to "WLC.domain.com" succeed.
I do have option 15 in DHCP enabled with "domain.com" (our domain name) but I have not tried removing that from DHCP. Other guests are active on the wireless and I do not want to break DHCP.
Another thing: In DNS, the forward lookup zone is "domain.com" and the A record FQDN is "WLC.domain.com". The reverse lookup zone is 1.1.1.adr as the capture page is on 184.108.40.206
I tried adding a new forward lookup zone with a wildcard, so it became "wlc.*" but that didnt fix it
The DNS server is hosted on a Server2012R2 box. The WLC is a Cisco 5510 as noted above