Posting this for the benefit of others, after failing to find the problem/resolution on my own.
Yesterday (Oct 2018), my Samsung J5 2016 phone failed to properly enable internet-wireless tethering. It never had a problem in the past, and I am fairly certain that I used tethering since date of the latest OS update (Jun 2018), at least in conjunction with an iOS device (iPad). But as of yesterday, tethering my Microsoft Surface Pro stopped working.
What actually failed:
- DNS resolution
Things I tried:
- I restarted the Android device
- I restarted the client (Surface Pro/Win 10)
- I renewed the DHCP lease. (
- Pinging the device.
- Pinging hosts by IP on the internet.
- Manually configuring the interface to use a DNS server (126.96.36.199)
- Manually configuring the interface to use the device as a DNS server (192.168.43.1)
What I did to resolve the issue:
First, on Windows, I used
ipconfig /all to determine the DHCP assigned IP address and DNS addresses. I noted these two were different:
- IP Address: 192.168.43.161
- IP Address of Gateway: 192.168.43.1
- DNS Address: 192.168.0.1
The DNS address looked bogus to me.
On the Windows device, I used Zenmap (nmap) to discover available ports, and saw that for 192.168.0.1, ports 80 and 443 were available, but not 53. I then did a scan of 192.168.43.1 and saw that 53 (UDP and TCP) were available.