As mentioned in an earlier post, I used TailScale to create a mesh network that connects all of my devices, and I used a cloud server located in AliCloud Beijing as an exit node, in order to access geographically restricted network services.
However, I noticed that I could not access the Internet at all when using that exit node. I thought it was a network connectivity issue with the relays, so I didn’t worry too much about it. But afterward, I noticed some other services on that server was not functioning, so I looked into it and found out that the problem was not that simple.
First I noticed that I couldn’t access the internet at all from the server, but
curl the IP address was working, which indicated the problem with DNS resolution.
resolvectl status showed that there were two DNS servers. I assumed this was the DNS server for the TailScale internal network (actually not, will elaborate later) since the IPs started with 100.100,
Link 2 (eth0) ...... Current DNS Server: 100.100.2.136 DNS Servers: 100.100.2.136 100.100.2.138
dig @100.100.2.136 baidu.com to check the response from the DNS server and got
connection timed out: no servers could be reached. The response from the command became normal after shutting down TailScale. So probably TailScale somehow affected the DNS resolution on the system.