How to fix proxyconnect tcp: dial tcp: connection refused (proxy) in Docker

echo "HTTP_PROXY: $HTTP_PROXY"
echo "HTTPS_PROXY: $HTTPS_PROXY"
echo "http_proxy: $http_proxy"
echo "https_proxy: $https_proxy"
echo "NO_PROXY: $NO_PROXY"

cat ~/.docker/config.json

{
  "proxies": {
    "default": {
      "httpProxy": "http://proxy.example.com:3128",
      "httpsProxy": "http://proxy.example.com:3128"
    }
  }
}

cat /etc/docker/daemon.json
sudo systemctl show --property=Environment docker

# Backup first
cp ~/.docker/config.json ~/.docker/config.json.backup

# Edit and remove proxies section
nano ~/.docker/config.json

unset HTTP_PROXY HTTPS_PROXY http_proxy https_proxy NO_PROXY no_proxy

# Check these files and remove proxy exports
~/.bashrc
~/.bash_profile
~/.zshrc
~/.profile
/etc/environment

# Remove proxy from daemon.json
sudo nano /etc/docker/daemon.json

# Remove systemd override if exists
sudo rm /etc/systemd/system/docker.service.d/http-proxy.conf
sudo systemctl daemon-reload
sudo systemctl restart docker

http://username:[email protected]:3128

{
  "proxies": {
    "default": {
      "httpProxy": "http://username:[email protected]:3128",
      "httpsProxy": "http://username:[email protected]:3128",
      "noProxy": "localhost,127.0.0.1,.internal.company.com"
    }
  }
}

sudo mkdir -p /etc/systemd/system/docker.service.d
sudo tee /etc/systemd/system/docker.service.d/http-proxy.conf << EOF
[Service]
Environment="HTTP_PROXY=http://username:[email protected]:3128"
Environment="HTTPS_PROXY=http://username:[email protected]:3128"
Environment="NO_PROXY=localhost,127.0.0.1,.internal.company.com"
EOF

sudo systemctl daemon-reload
sudo systemctl restart docker

sudo systemctl show --property=Environment docker
docker info | grep -i proxy

# Test proxy without authentication
curl -v -x http://proxy.example.com:3128 https://registry-1.docker.io/v2/

# Test proxy with authentication
curl -v -x http://username:[email protected]:3128 https://registry-1.docker.io/v2/

# Test if proxy is reachable at all
nc -zv proxy.example.com 3128
telnet proxy.example.com 3128

https_proxy=http://proxy.example.com:3128 wget -O- https://registry-1.docker.io/v2/

# Install cntlm
# Ubuntu/Debian
sudo apt-get install cntlm

# macOS
brew install cntlm

# Configure cntlm
sudo nano /etc/cntlm.conf

Username    your_username
Domain      YOUR_DOMAIN
Proxy       proxy.company.com:3128
Listen      3128

cntlm -H -d YOUR_DOMAIN -u your_username
# Enter password when prompted
# Copy the PassNTLMv2 line to /etc/cntlm.conf

sudo systemctl start cntlm
sudo systemctl enable cntlm

# Now proxy through localhost:3128
export HTTP_PROXY=http://localhost:3128
export HTTPS_PROXY=http://localhost:3128

pip install px-proxy
px --proxy=proxy.company.com:3128 --listen=3128

export NO_PROXY="localhost,127.0.0.1,::1,.local,internal-registry.company.com,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"

{
  "proxies": {
    "default": {
      "httpProxy": "http://proxy.example.com:3128",
      "httpsProxy": "http://proxy.example.com:3128",
      "noProxy": "localhost,127.0.0.1,::1,.local,.internal.company.com,internal-registry.company.com,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"
    }
  }
}

sudo tee /etc/systemd/system/docker.service.d/http-proxy.conf << EOF
[Service]
Environment="HTTP_PROXY=http://proxy.example.com:3128"
Environment="HTTPS_PROXY=http://proxy.example.com:3128"
Environment="NO_PROXY=localhost,127.0.0.1,.internal.company.com,10.0.0.0/8"
EOF

sudo systemctl daemon-reload
sudo systemctl restart docker

sudo systemctl restart docker
# Verify Docker is running
sudo systemctl status docker

# macOS
killall Docker && open -a Docker

# Windows PowerShell
Stop-Process -Name "Docker Desktop" -Force
Start-Process "C:\Program Files\Docker\Docker\Docker Desktop.exe"

# Test docker pull
docker pull hello-world

# Test with verbose output
docker pull alpine --debug

# Check if proxy is being used
docker info | grep -i proxy

# Linux
sudo journalctl -u docker.service -f

# Docker Desktop
# View logs from Troubleshoot > Get Support > Diagnose & Feedback