#75 [Bug]: Tabularis cannot connect to PostgreSQL via kubectl port-forward while pgAdmin works

[Anonymous]

Originally created by: getsueineko

Describe the bug

Description

Tabularis fails to connect to a PostgreSQL instance exposed locally via kubectl port-forward.
The client returns the following error:

Error: error communicating with database: failed to lookup address information: nodename nor servname provided, or not known

However, the same database connection works correctly when using pgAdmin and psql, which suggests the database itself and the port-forward are functioning correctly.

This indicates a potential issue in how Tabularis resolves or parses the connection parameters.

To Reproduce

Steps to reproduce

1.  Expose PostgreSQL service locally using port-forward:

kubectl port-forward svc/postgres 5432:5432
2. Connect using pgAdmin:
Host: localhost Port: 5432 Database: postgres User: postgres
Connection succeeds.
3. Attempt the same connection in Tabularis using identical parameters.
4. Tabularis returns:
Error: error communicating with database: failed to lookup address information: nodename nor servname provided, or not known

OS Version

macOS 26.3.1

Tabularis Version

v0.9.6

Relevant Log Output

[Anonymous]

Originally posted by: debba

Thanks for feedback.
Are you able to debug from code?
I am afk now but I can do a check later

[Anonymous]

Originally posted by: debba

@getsueineko i suspected is something related to localhost resolution.
But i am afk.
I sent the request to Claude Code If you want to do a check I referenced the commit in this issue if you want check.

I will check when I'll back

[Anonymous]

Originally posted by: getsueineko

I'm not rustman =)

I tried to debug the connection using tcpdump while connecting Tabularis to a PostgreSQL instance exposed via kubectl port-forward.

Command used:

sudo tcpdump -i lo0 -X port 53729

Connection sequence observed:

1.  TCP handshake completes successfully.
2.  Client sends PostgreSQL SSLRequest:

0000 0008 04d2 162f
3. Server responds with S (SSL supported).
4. Client starts TLS handshake (ClientHello).
The packet begins with:
16 03 03
5. Inside ClientHello the SNI value appears to be 127.0.0.1.
6. Server immediately responds with a TLS alert:
15 03 03 00 02 02 46
which corresponds to:
TLS fatal alert: certificate_unknown
7. After that the server closes the TCP connection (FIN).

So the connection flow looks like:

TCP connect
→ SSLRequest
→ server returns S
→ TLS ClientHello (SNI=127.0.0.1)
→ TLS alert certificate_unknown
→ connection closed.

This suggests the failure happens during TLS negotiation rather than PostgreSQL authentication.

The instance is accessed through kubectl port-forward, so the client connects to 127.0.0.1, while the PostgreSQL server certificate is issued for the Kubernetes service hostname like postgres.default.svc.cluster.local

[Anonymous]

Originally posted by: debba

I will definitely check it when I will be on pc

[Anonymous]

Originally posted by: debba

@getsueineko Can you check if [#77] has been solved the issue?
It's on main branch now.

[Anonymous]

Originally posted by: getsueineko

Version 0.9.7 - the same error occurs when selecting any of the four SSL modes, but now the menu for selecting databases works, meaning there is a connection, but at the same time, there isn't one.
Maybe the problem is in the http/https scheme?? I use http

[Anonymous]

Originally posted by: sycured

Version 0.9.7 - the same error occurs when selecting any of the four SSL modes, but now the menu for selecting databases works, meaning there is a connection, but at the same time, there isn't one. Maybe the problem is in the http/https scheme?? I use http

Why HTTP or HTTPS? It's a database, not an API.
This one is working on my side:

[Anonymous]

Originally posted by: getsueineko

I agree about scheme, however

[Anonymous]

Originally posted by: sycured

None of the SSL modes is working in your case?

In pgAdmin, click on your server name, go to the Properties tab on the right, and look at Connection String.

In my case, I see: sslmode=prefer (I've not set it manually)

[Anonymous]

Originally posted by: getsueineko

I've tried all the options, but to no avail. In pgdmin I see prefer mode. But in tabularis I have same error "Error: error occurred while attempting to establish a TLS connection: bad protocol version"

https://github.com/user-attachments/assets/e41cf5dc-c2d0-4126-b68f-b08a73f62186

[Anonymous]

Originally posted by: sycured

Can you tell me how you've deployed this PostgreSQL instance?
So I can try to reproduce your setup and issue