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forward

Forward ports between local system and remote targets (SSH hosts, Docker containers, Kubernetes pods).

Synopsis​

xec forward [options] <target> <port-mapping>
xec fwd [options] <target> <port-mapping>  # Alias

Description​

The forward command establishes port forwarding tunnels between your local machine and remote targets. It supports SSH port forwarding, Docker container port mapping, and Kubernetes pod port forwarding.

Arguments​

  • <target> - Target to forward from (SSH host, Docker container, or Kubernetes pod)
  • <port-mapping> - Port mapping specification (see Port Mapping Format below)

Port Mapping Format​

Port mappings can be specified as:

  • PORT - Forward same port number (local:PORT → remote:PORT)
  • LOCAL:REMOTE - Forward local port to different remote port
  • 0:REMOTE - Auto-select available local port
  • PORT1,PORT2 - Forward multiple ports (comma-separated)
  • LOCAL1:REMOTE1,LOCAL2:REMOTE2 - Multiple custom mappings

Options​

General Options​

  • -p, --profile <profile> - Configuration profile to use
  • -i, --interactive - Interactive mode for setting up port forwarding
  • -b, --bind <address> - Local bind address (default: 127.0.0.1)
  • -r, --reverse - Reverse port forwarding (remote to local) - Not yet implemented
  • --background - Run port forwarding in background
  • -v, --verbose - Enable verbose output
  • -q, --quiet - Suppress output
  • --dry-run - Preview port forwarding without establishing

Examples​

Basic Port Forwarding​

Forward common service ports:

# Forward PostgreSQL from SSH host
xec forward hosts.db 5432

# Forward MySQL from Docker container
xec forward containers.mysql 3306

# Forward Redis from Kubernetes pod
xec forward pods.redis 6379

Custom Port Mapping​

Map to different local ports:

# Forward remote port 80 to local port 8080
xec forward pods.webapp 8080:80

# Forward remote PostgreSQL to local port 15432
xec forward hosts.database 15432:5432

# Forward multiple services
xec forward hosts.server 8080:80,8443:443

Auto Port Selection​

Let Xec choose available local ports:

# Auto-select local port for remote service
xec forward hosts.api 0:3000

# Auto-select for multiple ports
xec forward containers.app 0:8080,0:9090

Different Bind Addresses​

Control local bind address:

# Bind to all interfaces (accessible from network)
xec forward --bind 0.0.0.0 hosts.web 8080:80

# Bind to specific interface
xec forward --bind 192.168.1.100 containers.api 3000

# Default: localhost only (127.0.0.1)
xec forward hosts.db 5432

Background Mode​

Run port forwarding in background:

# Start forwarding in background
xec forward --background pods.service 8080

# Multiple background forwards
xec forward --background hosts.db 5432
xec forward --background hosts.cache 6379

Interactive Mode​

Use interactive prompts for configuration:

# Interactive setup
xec forward -i

# Prompts for:
# - Target type (SSH/Docker/Kubernetes)
# - Specific target selection
# - Remote port
# - Local port configuration
# - Additional options

Target Types​

SSH Hosts​

Forward ports through SSH tunnels:

# Basic SSH forwarding
xec forward hosts.prod 3000

# Multiple SSH forwards
xec forward hosts.gateway 80,443,3306

# Custom SSH host configuration
xec forward hosts.bastion 22222:22

Docker Containers​

Forward ports from Docker containers:

# Forward from running container
xec forward containers.webapp 8080

# Forward multiple container ports
xec forward containers.stack 3000,3001,3002

# Uses Docker networking internally
xec forward containers.db 27017

Kubernetes Pods​

Forward ports from Kubernetes pods:

# Forward from pod
xec forward pods.frontend 3000

# Forward with namespace (from config)
xec forward pods.backend 8080

# Multiple pod ports
xec forward pods.monitoring 9090,9093,3000

Advanced Usage​

Multiple Port Forwarding​

Forward multiple ports simultaneously:

# Forward web and API ports
xec forward hosts.server 80,443,3000,8080

# Different local/remote mappings
xec forward containers.stack 8080:80,8443:443,13306:3306

# Mix auto and fixed ports
xec forward pods.services 0:9090,8080:8080,0:3000

Tunnel Chains​

Create complex forwarding scenarios:

# Forward through jump host (configured in SSH)
xec forward hosts.internal-db 5432

# Access container through SSH tunnel
xec forward hosts.docker-host 8080:80

# Kubernetes through bastion
xec forward hosts.k8s-bastion 6443:6443

Service Discovery​

Use with service discovery patterns:

# Forward all database ports
xec forward hosts.db 5432,6379,27017

# Forward monitoring stack
xec forward pods.monitoring 3000,9090,9093,8086

# Forward development services
xec forward containers.dev 3000,3001,4200,8080

Configuration​

Set default forward options in .xec/config.yaml:

targets:
  hosts:
    database:
      type: ssh
      host: db.internal
      username: deploy
      # SSH config for tunneling
      localForward:
        - 5432:localhost:5432
        - 6379:localhost:6379

commands:
  forward:
    bind: "127.0.0.1"
    background: false

Network Security​

Bind Address Security​

  • 127.0.0.1 (default) - Local access only
  • 0.0.0.0 - Network accessible (use with caution)
  • Specific IP - Bind to specific network interface

Firewall Considerations​

# Local-only (safe default)
xec forward hosts.db 5432

# Network accessible (requires firewall rules)
xec forward --bind 0.0.0.0 hosts.api 8080

# Check local port usage
netstat -an | grep LISTEN

Troubleshooting​

Common Issues​

Port already in use:

# Use different local port
xec forward hosts.service 18080:8080

# Or auto-select
xec forward hosts.service 0:8080

Permission denied (ports < 1024):

# Use higher local port
xec forward hosts.web 8080:80

# Or use sudo (not recommended)
sudo xec forward hosts.web 80

Connection refused:

  • Verify target service is running
  • Check firewall rules
  • Confirm target configuration

Debugging​

# Verbose output for debugging
xec forward -v hosts.service 3000

# Dry run to test configuration
xec forward --dry-run pods.app 8080:80

# Check active forwards
ps aux | grep "xec forward"
netstat -an | grep LISTEN

Cleanup​

Port forwards are automatically cleaned up when:

  • Process is terminated (Ctrl+C)
  • Terminal session ends
  • System shutdown

For background forwards:

# Find forward processes
ps aux | grep "xec forward"

# Kill specific forward
kill <pid>

# Kill all forwards
pkill -f "xec forward"

Performance Considerations​

  • SSH forwarding adds encryption overhead
  • Docker forwarding uses socat for efficiency
  • Kubernetes forwarding uses native kubectl
  • Multiple ports share the same tunnel when possible

Limitations​

  • Reverse forwarding (-r) not yet implemented
  • UDP forwarding not supported
  • Dynamic port forwarding (SOCKS) not available
  • Maximum 65535 ports per target
  • on - Execute commands on SSH hosts
  • in - Execute commands in containers/pods
  • copy - Transfer files to/from targets

Exit Codes​

  • 0 - Success, forwarding established
  • 1 - General error
  • 2 - Invalid arguments
  • 3 - Target not found
  • 4 - Port binding failed
  • 5 - Network error