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We have an airgapped network composed of an Ubuntu 16.04 server and a Pepwave Peplink AP Pro 300M Wireless Access point. The goal is to allow consumer users to hit this access point but, when they are on it, they are only able to access the website(s) on the server. By "airgapped" I mean that the network has no Internet/WAN access, nor is it supposed to have such access. There literally is no connection to a router or to the Internet.

We have configured Bind9 as a DNS server so that specific domains resolve to the local web server.

Essentially it looks like this:

  • web server / DNS server 192.168.1.18
  • Access Point: 192.168.1.22
  • AP manages DHCP and hands out addresses from 192.168.1.80 to 192.168.1.254
  • AP Gateway: 192.168.1.18
  • AP DNS: 192.168.1.18
  • Landing Page: 192.168.1.18

Overall this is working: if you connect to the access point and go to one of the airgapped sites setup with DNS in bind (e.g. myinfo.myservers.com) you will be redirected to the landing page and you are running the web app we want you to be running. Running an nslookup myinfo properly resolves to 192.168.1.18

However there is one significant annoyance: If you connect to this via an Android phone, you will occasionally see a notification such as "Android System, Wi-Fi has no Internet Access, Tap for options". The sites we want you to hit still work, though.

I presume Android is doing some behind-the-scenes checking for Internet access? How can we setup our DNS or this network in general so the wireless devices seem happy? Are there specific responses or IP addresses that must respond?

Esa Jokinen
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Dave Collins
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    You should be able to find what DNS records are being looked up by enabling query logging in BIND. Running a packet sniffer would show what other traffic is being attempted by the clients. – bodgit Sep 27 '17 at 12:39
  • Great suggestion @bodgit - If you want to post that as the answer I will mark it. I'm kind of saddened, however, by how many web requests an Android phone (without even a browser open) makes!! :-o – Dave Collins Sep 28 '17 at 12:15

1 Answers1

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You should be able to find what DNS records are being looked up by enabling query logging in BIND.

Running a packet sniffer would show what other traffic is being attempted by the clients.

bodgit
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