Why choose WireGuard on EC2

WireGuard is a modern VPN protocol focused on simplicity, performance, and strong cryptography. Deploying WireGuard on an AWS EC2 instance gives you a lightweight, high-throughput VPN endpoint under your control — ideal for site-to-site tunnels, secure remote access for administrators, or creating a dedicated IP egress point for applications. This guide walks you through a production‑minded setup with emphasis on security, routing, and operational considerations.

Prerequisites and design choices

Before you start, make these decisions and gather details:

  • Instance type: For small to medium workloads, t3.micro/t3.small work; for heavier throughput choose network‑optimized instances (e.g., c5, m5) with enhanced networking.
  • OS: Ubuntu LTS (20.04/22.04) or Amazon Linux 2 are common choices. Commands below assume Debian/Ubuntu-style package management; adapt package commands for yum/dnf on Amazon Linux.
  • VPC and subnet: Choose a private subnet or public subnet depending on whether you want the server to have a public Elastic IP (EIP). For simplicity, this guide assumes the EC2 instance has an EIP and will NAT client traffic to the internet.
  • Security posture: Follow principle of least privilege: open only necessary ports on Security Groups, enable CloudWatch and AWS logging if required, and consider IAM roles for operational tasks.

Step 1 — Provision EC2 and configure networking

Launch an EC2 instance with the chosen OS and attach an Elastic IP if you need a stable public endpoint. Configure the Security Group to allow UDP traffic on your chosen WireGuard port (default 51820) and SSH for administration.

  • Inbound rules: UDP 51820/32 from desired client IP ranges (or 0.0.0.0/0 if clients are dynamic).
  • Inbound rules: TCP 22/32 restricted to administrative IPs.
  • Outbound rules: allow required egress (typically all outbound).

Note: For higher security, restrict UDP port to the minimal set of client IPs; you can adjust as clients change.

Step 2 — Install WireGuard

On Ubuntu/Debian:

Command: apt update && apt install -y wireguard iptables persistent

On Amazon Linux 2 or other distros, ensure kernel module support (wireguard tools and wireguard-module or use the wireguard-go userspace implementation if needed).

Step 3 — Key generation and basic server config

Generate long-term server keys. WireGuard keys are Curve25519 public/private pairs.

Command: wg genkey | tee /etc/wireguard/server_private.key | wg pubkey > /etc/wireguard/server_public.key

Set secure permissions on the private key: chmod 600 /etc/wireguard/server_private.key.

Create the server configuration file /etc/wireguard/wg0.conf with the following essential fields (replace placeholders):

Interface block should include:

  • PrivateKey = (contents of server_private.key)
  • Address = 10.10.0.1/24 (select a private subnet dedicated to the VPN)
  • ListenPort = 51820
  • PostUp/PostDown rules to handle NAT and IP forwarding — we cover these in the firewall section.

Example (conceptual format; insert actual key values):

Interface: PrivateKey = [SERVER_PRIVATE_KEY], Address = 10.10.0.1/24, ListenPort = 51820

Client keys and peer configuration

On each client, generate a keypair similarly. Add a Peer stanza to the server config for each client with fields:

  • PublicKey = client public key
  • AllowedIPs = the client’s VPN IP (e.g., 10.10.0.2/32) or CIDR ranges to route over VPN
  • Optional: PersistentKeepalive = 25 (for clients behind NAT to maintain the mapping)

On the client, use the server’s public key and endpoint (EIP:51820) to form its config and route directives (e.g., AllowedIPs = 0.0.0.0/0 to tunnel all traffic through the server, or a narrower set for split tunneling).

Step 4 — Enable IP forwarding and NAT

Enable IPv4 forwarding system‑wide:

Command: sysctl -w net.ipv4.ip_forward=1

Persist by adding net.ipv4.ip_forward=1 to /etc/sysctl.conf.

Configure NAT so VPN clients can reach the Internet through the EC2 host if using a public EIP:

iptables example (IPv4):

iptables -t nat -A POSTROUTING -s 10.10.0.0/24 -o eth0 -j MASQUERADE

Save iptables rules with iptables-persistent or an equivalent mechanism so they survive reboots.

Alternative: nftables

If your system uses nftables, create an equivalent masquerade rule:

nft add table nat; nft ‘add chain nat post { type nat hook postrouting priority 100 ; }’; nft add rule nat post oifname “eth0” ip saddr 10.10.0.0/24 masquerade

Step 5 — Start and enable WireGuard

Bring up the interface with systemd integration:

Command: systemctl enable wg-quick@wg0 && systemctl start wg-quick@wg0

Verify status and peers:

Command: wg show

Check that the interface has the correct address and that you can ping the client IPs once clients are connected.

Step 6 — Client configuration and testing

On client devices (Linux, Windows, macOS, iOS, Android), install a WireGuard client and import the generated client configuration. Key fields:

  • Interface: PrivateKey, Address (e.g., 10.10.0.2/32), DNS (optional)
  • Peer: PublicKey (server), Endpoint (EIP:51820), AllowedIPs (0.0.0.0/0 for full tunnel or narrower)
  • PersistentKeepalive = 25 recommended for mobile/roaming clients

Test connectivity: ping 10.10.0.1 (server), then ping an external IP (e.g., 1.1.1.1) if you have NAT enabled.

Performance tuning and practical tips

  • MTU: Default MTU 1420–1424 often works well when tunneling over UDP — reduce if you see fragmentation. Set MTU in both server and client configs (e.g., MTU = 1420).
  • CPU and crypto offload: For high throughput, choose instance types that support ENA and sufficient vCPUs. WireGuard scales well but is CPU-bound for encryption — consider larger instances for many concurrent users.
  • Logging: WireGuard itself is minimal on logs. Use systemd journal plus connection monitoring (wg show) and CloudWatch for system metrics.
  • DNS leakage: If tunneling all traffic, set VPN clients to use a DNS that respects privacy (e.g., internal resolver or 1.1.1.1) in the client config’s DNS field.

Security hardening

  • Limit Security Group exposure: Only open UDP port to required IP ranges where practical.
  • Rotate keys periodically: Implement a rotation process for server and high‑privilege client keys. Update peer configs atomically to avoid downtime.
  • Use IAM roles: Avoid embedding AWS credentials on the instance. Use IAM roles for any AWS API access.
  • Firewall rules: Apply iptables/nftables to restrict forwarded traffic to necessary ports and destination ranges. Deny traffic between clients unless explicitly required.
  • Host hardening: Keep the OS and kernel patched, disable unused services, and apply fail2ban/SSH rate limits to secure administration access.

Scaling, HA, and advanced deployment patterns

Single EC2 instances are fine for small deployments, but scale and high availability require more planning:

  • Multiple endpoints: Launch multiple WireGuard endpoints in different AZs. Use Amazon Route 53 latency-based routing or a client-side list of endpoints for failover.
  • Autoscaling for ephemeral clients: If you need many short-lived connections, use an autoscaling group behind Network Load Balancer (NLB) with UDP target support and a shared key provisioning system (e.g., central auth service issuing client configs).
  • Centralized user management: Use a small internal PKI or automation scripts (Terraform/Ansible) to create client keypairs, push peer entries, and reload WireGuard without manual edits.
  • Stateful flows: Remember that WireGuard is stateless per se; when using multiple endpoints, session persistence and routing must be handled on the client or via a stateful load balancer solution.

Troubleshooting checklist

  • Confirm Security Group and OS firewall allow UDP 51820 inbound and responses outbound.
  • Verify server private key matches the public key published to clients and vice versa.
  • Check sysctl net.ipv4.ip_forward is enabled and NAT rules are present if routing internet traffic.
  • Use tcpdump or tshark on the WireGuard UDP port to verify packets arriving at the server.
  • If clients can access LAN resources but not the internet, double‑check MASQUERADE rule uses the correct external interface name (eth0, ens5, etc.).

Automation snippets and operational workflow

For reproducibility, create automation scripts or use configuration management to:

  • Generate and store keys securely (consider AWS KMS or Secrets Manager for storing public/private key material).
  • Deploy wg0.conf templates and restart wg-quick in a controlled manner (systemctl restart wg-quick@wg0).
  • Rotate keys by adding new peer entries with overlapping allowed IPs and phasing out old keys.

By following the steps above you can deploy a secure, high-performance WireGuard VPN on AWS EC2 that meets the needs of administration, secure remote access, or controlled egress via a dedicated IP. The architecture is flexible: for production use, add monitoring, backups, and key rotation processes to maintain operational security.

Published by Dedicated-IP-VPN