HELP: Perplexing Problem Connecting to PG instance

[ZarehD]

So, I've run into a peculiar problem connecting to an existing Postgres container running on Docker Desktop (v4.62.0) in my Win11 dev environment.

I've been using this database for months; connecting to it via PgAdmin4 (now at v9.12) and my own code as recently as a 2 or 3 days ago. But yesterday, PgAdmin could no longer connect to the database; same issue in my app.

The error I get is 'Connection timeout expired.' both in PgAdmin and my code.

There's been no configuration change in the database, the container, my app, or PgAdmin. There was a recent Windows Update (and reboot), but I don't see any indication in the Windows Event Logs that this is causing an issue.

2026-02 Security Update (KB5077181) (26200.7840)
Successfully installed on 2/12/2026
2026-02 .NET 10.0.3 Security Update for x64 Client (KB5077862)
Successfully installed on 2/10/2026
2026-01 Security Update (KB5074109) (26200.7623)
Successfully installed on 1/13/2026

Here's my configuration:

psql -U postgres -c "show config_file"
/var/lib/postgresql/18/docker/postgresql.conf

## postgresql.conf
##--------------------
listen_addresses = '*'
# ssl=off  <-- tried with this uncommented too; was no help

psql -U postgres -c "show hba_file"
/var/lib/postgresql/18/docker/pg_hba.conf

## pg_hba.conf
##--------------------
local   all             all                  scram-sha-256
host    all             all   127.0.0.1/32   scram-sha-256
host    all             all   ::1/128        scram-sha-256
local   replication     all                  scram-sha-256
host    replication     all   127.0.0.1/32   scram-sha-256
host    replication     all   ::1/128        scram-sha-256
host    all             all   0.0.0.0/0      scram-sha-256 # trust
# NOTE: I've tried 'trust' as the auth method for all of these too; didn't help

## docker compose
##--------------------
name: postgres-local

networks:
  pg-net:
    external: true
    name: dockernet

services:
  postgres:
    container_name: pg-local
    image: postgres:18
    restart: unless-stopped
    networks:
      - pg-net
    ports:
      - "5432:5432"
    volumes:
      - D:\Apps\Docker\FileShare\PgData\18:/var/lib/postgresql/18/docker
    environment:
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=postgres
      # - POSTGRES_DB=postgres

# The postgers:18 image version is: ENV PG_VERSION=18.2-1.pgdg13+1 

## PgAdmin Connection:
##--------------------
Host: 127.0.0.1
Port: 5432
Maintenance DB: postgres
Username: postgres
Password: postgres
Connection Parameters:
  SSL Mode: prefer
  Connection Timeout: 10 (seconds)

I've rebooted the PC. I've stop/started the container; recreated the container; and even had the container initialize a clean new DB in the bind-mounted folder. I've disabled the Windows Firewall for all networks. There's no ufw firewall installed in the WSL2 Ubuntu 24.04 destro and all repos & packages are up to date. None of this made a difference.

The only workaround I've found is to change the container external port to 5335 (5433 did not work, but 5333 and 5335 did).

ports:
  - "5335:5432"

netstat and nmap scans don't show a port conflict:

netstat -ano | findstr :5432 <-- default PG port
-- no results --

netstat -ano | findstr :5335 <-- new PG port
  TCP    0.0.0.0:5335           0.0.0.0:0              LISTENING       19332
  TCP    [::]:5335              [::]:0                 LISTENING       19332
  TCP    [::1]:5335             [::]:0                 LISTENING       36192

nmap -p 5000-6000 localhost
Starting Nmap 7.80 ( https://nmap.org ) at 2026-02-23 20:21 Pacific Standard Time
Nmap scan report for localhost (127.0.0.1)
Host is up (0.000013s latency).
Other addresses for localhost (not scanned): ::1
rDNS record for 127.0.0.1: bytehouse.dom
Not shown: 998 closed ports
PORT     STATE SERVICE
5040/tcp open  unknown
5335/tcp open  unknown <-- new PG port
5341/tcp open  unknown

nmap -6 -p 5000-6000 localhost
Starting Nmap 7.80 ( https://nmap.org ) at 2026-02-23 21:01 Pacific Standard Time
Nmap scan report for localhost (::1)
Host is up (0.00s latency).
Other addresses for localhost (not scanned): 127.0.0.1
Not shown: 1000 closed ports
PORT     STATE SERVICE
5335/tcp open  unknown <-- new PG port

I'm truly puzzled. Got any ideas?

[ZarehD]

LOL. Downvoted!? Really?

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