Cannot connect to a postgres instance through tailscale

[csweichel]

Bug description

I'm trying to connect to a postgres instance through tailscale. The DNS name resolves just fine, but psql cannot connect. Unsetting PGHOSTADDR has no effect. When using the IP instead of the name things work well. When I attempt the same connection from a VM outside of Gitpod but through tailscale, everything works as expected.

[kylos101]

Hey @csweichel , I recreated the problem here.

I'm having trouble resolving DNS from Gitpod when using Tailscale Magic DNS for machines on my tailscale network. Interesting how when I netcat -u 100.100.100.100 -v, I get different results from both environments:

VM
ubuntu@database:~$ netcat -u 100.100.100.100 53 -v
Connection to 100.100.100.100 53 port [udp/domain] succeeded!
�"gitpod-kyle-brennan-tailscale-teskylos101githubbeta tailscalenet�"gitpod-kyle-brennan-tailscale-teskylos101githubbeta tailscalenet�"gitpod-kyle-brennan-tailscale-teskylos101githubbeta tailscalenet�"gitpod-kyle-brennan-tailscale-teskylos101githubbeta tailscalenet�"gitpod-kyle-brennan-tailscale-teskylos101githubbeta tailscalenet

Gitpod
gitpod /workspace/tailscale-test $ netcat -u 100.100.100.100 53 -v
Connection to 100.100.100.100 53 port [udp/domain] succeeded!
�����^C

Almost like the Tailscale response (for Gitpod) was lacking data, was stripped out...or something silly is happening in my terminal. 😆

[csweichel]

I've created a local VM, ran postgres and dnsmasq to provide name resolution. I was successfully able to connect to the postgres instance from my workspace through tailscale.

The next thing to try is to replicate the RDS setup directly.

[sagor999]

I believe this was due to blocking all UDP traffic, which tailscale relies upon.
Since we disabled UDP firewall block, this should work now.
I will close this, but please re-open if it is not resolved.