Privacy March 20, 2025 ⏱ 6 min read

VPN Protocols Compared: WireGuard, OpenVPN, and IPSec

An in-depth comparison of modern VPN protocols — performance, security, configuration, and when to use each one.

vpnwireguardopenvpnipsecprivacy

Why VPNs Still Matter in 2025

Even with widespread HTTPS adoption, a VPN remains a critical layer in any serious privacy or security posture. Public Wi-Fi networks, ISP-level traffic logging, geo-restricted content, and corporate network access all demand encrypted tunnels between endpoints. But not all VPN protocols are created equal. The protocol you choose directly impacts your throughput, latency, attack surface, and operational complexity.

This article breaks down three dominant VPN protocols — WireGuard, OpenVPN, and IPSec/IKEv2 — comparing their architecture, configuration, performance, and ideal use cases.

WireGuard

Overview

WireGuard is a modern, lightweight VPN protocol that lives inside the Linux kernel (since 5.6). It was designed by Jason Donenfeld with a philosophy of minimal code and cryptographic simplicity. The entire codebase is roughly 4,000 lines of code, compared to OpenVPN’s 100,000+. This makes it significantly easier to audit.

WireGuard uses a fixed set of modern cryptographic primitives:

ChaCha20 for symmetric encryption
Poly1305 for authentication
Curve25519 for key exchange
BLAKE2s for hashing
SipHash24 for hashtable keys

Configuration Example

A minimal WireGuard peer configuration looks like this:

# /etc/wireguard/wg0.conf
[Interface]
PrivateKey = yAnz5TF+lXXJte14tji3zlMNq+hd2rYUIgJBgB3fBmk=
Address = 10.0.0.2/24
DNS = 1.1.1.1
ListenPort = 51820

[Peer]
PublicKey = xTIBA5rboUvnH4htodjb6e697QjLERt1NAB4mZqp8Dg=
AllowedIPs = 0.0.0.0/0
Endpoint = vpn.example.com:51820
PersistentKeepalive = 25

Bringing the tunnel up is a single command:

sudo wg-quick up wg0

Pros and Cons

✅ Pros	❌ Cons
Extremely fast (kernel-space)	No built-in dynamic IP handling
Tiny attack surface (~4K LOC)	Fixed cryptographic suite (no cipher agility)
Simple configuration	No built-in user authentication (needs wrapper)
Roaming-friendly (UDP-based)	Stores peer IPs in memory (privacy consideration)
First-class Linux kernel support	Less mature ecosystem than OpenVPN

OpenVPN

Overview

OpenVPN has been the industry workhorse since 2001. It operates in user-space, uses OpenSSL (or mbed TLS) for cryptography, and supports both UDP and TCP transports. Its maturity means wide platform support, extensive documentation, and battle-tested deployments across enterprises worldwide.

OpenVPN can operate in two modes:

Routed (tun) — Layer 3, most common
Bridged (tap) — Layer 2, useful for broadcast-dependent protocols

Configuration Example

A basic OpenVPN server config:

# /etc/openvpn/server.conf
port 1194
proto udp
dev tun
ca /etc/openvpn/ca.crt
cert /etc/openvpn/server.crt
key /etc/openvpn/server.key
dh /etc/openvpn/dh2048.pem

server 10.8.0.0 255.255.255.0
push "redirect-gateway def1 bypass-dhcp"
push "dhcp-option DNS 1.1.1.1"

cipher AES-256-GCM
auth SHA256
tls-version-min 1.2

keepalive 10 120
persist-key
persist-tun
verb 3

Client connection:

sudo openvpn --config /etc/openvpn/client.ovpn

Pros and Cons

✅ Pros	❌ Cons
Extremely flexible and configurable	Slower than WireGuard (user-space)
TCP mode can bypass firewalls (port 443)	Complex PKI setup required
Mature, well-audited codebase	Larger attack surface (~100K+ LOC)
Supports certificate-based auth and MFA	Higher CPU usage under load
Plugin architecture (LDAP, RADIUS, PAM)	Configuration can be error-prone

IPSec / IKEv2

Overview

IPSec is a suite of protocols operating at the network layer (Layer 3), standardized by the IETF. Combined with IKEv2 (Internet Key Exchange version 2) for session negotiation, it forms one of the most robust VPN solutions available — and it’s the protocol behind most corporate and mobile VPN deployments.

IPSec works in two modes:

Transport mode — encrypts only the payload (host-to-host)
Tunnel mode — encrypts the entire IP packet (gateway-to-gateway)

Common implementations include strongSwan, Libreswan, and native OS stacks on Windows, macOS, iOS, and Android.

Configuration Example (strongSwan)

# /etc/ipsec.conf
conn myvpn
    keyexchange=ikev2
    ike=aes256-sha256-modp2048!
    esp=aes256-sha256!
    left=%defaultroute
    leftauth=pubkey
    leftcert=server.crt
    [email protected]
    right=%any
    rightauth=eap-mschapv2
    rightsourceip=10.10.10.0/24
    rightdns=1.1.1.1
    auto=add

Pros and Cons

✅ Pros	❌ Cons
Native OS support (no third-party apps)	Complex configuration
Excellent for mobile (MOBIKE handles roaming)	Debugging is notoriously difficult
Strong standards-based security	Can be blocked by restrictive firewalls
Kernel-level performance	Certificate and EAP setup overhead
IKEv2 reconnects seamlessly	Multiple interacting components (IKE, ESP, AH)

Performance Benchmarks

Real-world performance varies by hardware, but the following table reflects general throughput characteristics measured on modern x86 hardware with a 1 Gbps link:

Protocol	Throughput	Latency Overhead	CPU Usage	Handshake Time
WireGuard	~900 Mbps	~0.5 ms	Very Low	~1 RTT
OpenVPN (UDP)	~400-600 Mbps	~1-3 ms	Moderate-High	~2-4 RTT
OpenVPN (TCP)	~200-400 Mbps	~3-8 ms	High	~4-6 RTT
IPSec/IKEv2	~700-850 Mbps	~0.5-1 ms	Low	~2 RTT

WireGuard’s kernel-space execution and lean cryptographic stack give it a clear edge. IPSec benefits from kernel-level processing as well, while OpenVPN’s user-space design introduces context-switching overhead.

Security Comparison

Criteria	WireGuard	OpenVPN	IPSec/IKEv2
Codebase size	~4,000 LOC	~100,000+ LOC	Varies (large)
Cipher agility	No (fixed suite)	Yes (configurable)	Yes (negotiated)
Forward secrecy	Yes (per-handshake)	Yes (with DH/ECDH)	Yes (with PFS)
Formal verification	Partial	No	Partial
CVE history	Minimal	Moderate	Extensive
Post-quantum readiness	Not yet	Not yet	Research phase

WireGuard’s lack of cipher agility is both a strength and a limitation. It eliminates downgrade attacks and misconfiguration, but if a vulnerability is found in one of its primitives, the entire protocol must be updated. OpenVPN and IPSec offer negotiation flexibility at the cost of a larger configuration surface.

When to Use Which

Choose WireGuard when:

You need maximum throughput with minimal overhead
You’re building a mesh network (e.g., with Tailscale or Netmaker)
You want simple peer-to-peer connectivity
You control both endpoints and prefer a modern stack

Choose OpenVPN when:

You need to traverse restrictive firewalls (TCP/443)
Your deployment requires certificate-based authentication with LDAP/RADIUS
You’re running on legacy systems that don’t support WireGuard
You need granular control over every aspect of the tunnel

Choose IPSec/IKEv2 when:

You’re deploying on mobile devices that need seamless roaming
You want native OS support without installing third-party software
You’re operating in a corporate environment with existing PKI infrastructure
You need standards-compliant interoperability between vendors

Final Thoughts

There is no universally “best” VPN protocol. WireGuard leads in performance and simplicity, OpenVPN dominates in flexibility and firewall traversal, and IPSec/IKEv2 excels in mobile and enterprise scenarios. Evaluate your threat model, infrastructure constraints, and operational requirements before committing to a stack. In many architectures, running more than one protocol for different use cases is the pragmatic choice.