🔒 About L2TP/IPSec

L2TP/IPSec combines Layer 2 Tunneling Protocol with IPSec encryption for secure VPN connections. While more secure than PPTP, it's an older protocol that modern alternatives like WireGuard and IKEv2 have largely superseded.

Protocol Security Comparison

⚠️ L2TP/IPSec (This Guide)

Moderate security with IPSec
Can be blocked by firewalls
Slower than modern protocols
Double encapsulation overhead
Pre-shared key vulnerabilities

✅ WireGuard (Recommended)

State-of-the-art cryptography
Minimal attack surface
Best performance
Simple configuration
Available in RouterOS 7+

✅ IKEv2/IPSec

Modern IPSec implementation
Better than L2TP/IPSec
MOBIKE support
Hardware acceleration
Enterprise standard

Mikrotik RouterOS Requirements

Prerequisites

RouterOS version 6.0 or higher
IPSec package installed (default in most installations)
Sufficient CPU for encryption (especially for AES-256)
Administrator access to router
TorGuard VPN account with L2TP support

IPSec Encryption Options

Parameter	AES-128 (Faster)	AES-256 (Stronger)	Recommendation
Encryption	aes-128-cbc	aes-256-cbc	AES-128 for most users
Hash	SHA1	SHA1	Limited by L2TP spec
DH Group	None	None	Not used with PSK
CPU Impact	~10-20%	~20-40%	Monitor router load

Step-by-Step Configuration

1Access Mikrotik Router

Connect using one of these methods:

WebFig: http://[router-ip] (ensure WebFig interface)
WinBox: Download from mikrotik.com (recommended)
SSH: ssh admin@[router-ip]

2Configure IPSec Proposal

Navigate to: IP → IPsec → Proposals

Configure encryption and authentication algorithms

IPSec Proposal Settings:

✓ Enabled
Auth Algorithms: sha1 only
Encr Algorithms: aes-128-cbc (or aes-256-cbc for higher security)
PFS Group: none

3Create L2TP Interface

Navigate to: Interfaces → Add New → L2TP Client

Basic L2TP client settings

General Settings:

✓ Enabled
Name: TorGuard-L2TP

Dial Out Settings:

Connect To: [VPN Server IP]
User: Your TorGuard Username
Password: Your TorGuard Password
✓ Use IPsec
IPsec Secret: torguard
✗ Dial On Demand (unchecked)
✗ Add Default Route (unchecked)

4Disable Fasttrack (Important!)

Navigate to: IP → Firewall → Filter Rules

⚠️ Critical Step

Find any rules with "fasttrack connection" and disable them. Fasttrack bypasses connection tracking and will break VPN functionality.

5Configure NAT Masquerade

Navigate to: IP → Firewall → NAT → Add New

NAT Rule:

Chain: srcnat
Out Interface: TorGuard-L2TP
Action: masquerade

6Setup Selective Routing (Optional)

For routing specific devices through VPN:

A. Create Mangle Rule

Navigate to: IP → Firewall → Mangle → Add New

Mangle Settings:

✓ Enabled
Chain: prerouting
Src Address: 192.168.88.100-192.168.88.150 (example range)
Action: mark routing
New Routing Mark: VPN-Route
✓ Passthrough

B. Create Route

Navigate to: IP → Routes → Add New

Route Settings:

Dst Address: 0.0.0.0/0
Gateway: TorGuard-L2TP
Routing Mark: VPN-Route

7Configure DNS

Navigate to: IP → DNS

TorGuard DNS Servers:

Primary: 10.8.0.1
Secondary: 10.8.8.1
✓ Allow Remote Requests

Traffic Flow Visualization

Selective VPN Routing

LAN Device
(192.168.88.100)

→

Mangle Rule
(Mark: VPN-Route)

→

Routing Table
(Gateway: L2TP)

→

TorGuard VPN

Performance Optimization

🚀 Optimization Tips

CPU Usage Reduction:

Use AES-128 instead of AES-256 if security permits
Enable hardware encryption if your RouterBoard supports it
Limit concurrent connections
Consider upgrading to RouterOS 7 for WireGuard

Connection Stability:

Set keepalive timeout: 10 seconds
Enable DPD (Dead Peer Detection)
Use stable DNS servers
Monitor MTU issues (typically 1400 for L2TP/IPSec)

Troubleshooting

Connection Fails

Verify server IP is correct
Check username/password
Ensure ports 500, 4500 (UDP) open
Disable fasttrack rules

No Internet Access

Check NAT masquerade rule
Verify DNS configuration
Test with manual DNS (8.8.8.8)
Check firewall filter rules

Poor Performance

Monitor CPU usage (/system resource)
Switch to AES-128
Check for packet fragmentation
Consider protocol alternatives

Command Line Configuration

For advanced users, here's the complete configuration via CLI:

# IPSec Proposal
/ip ipsec proposal
set [ find default=yes ] auth-algorithms=sha1 enc-algorithms=aes-128-cbc pfs-group=none

# L2TP Client
/interface l2tp-client
add connect-to=SERVER_IP disabled=no ipsec-secret=torguard name=TorGuard-L2TP \
    password=YOUR_PASSWORD use-ipsec=yes user=YOUR_USERNAME

# NAT Rule
/ip firewall nat
add action=masquerade chain=srcnat out-interface=TorGuard-L2TP

# Mangle Rule (optional - for selective routing)
/ip firewall mangle
add action=mark-routing chain=prerouting new-routing-mark=VPN-Route \
    passthrough=yes src-address=192.168.88.100-192.168.88.150

# Route (optional - for selective routing)
/ip route
add distance=1 gateway=TorGuard-L2TP routing-mark=VPN-Route

# DNS
/ip dns
set allow-remote-requests=yes servers=10.8.0.1,10.8.8.1

Security Best Practices

✅ Recommendations

Firewall Rules: Create specific allow rules for VPN traffic only
Logging: Enable connection logging for audit trails
Updates: Keep RouterOS updated for security patches
Backup: Export configuration before making changes
Migration Plan: Consider upgrading to WireGuard or IKEv2

When to Use L2TP/IPSec

L2TP/IPSec is suitable when:

WireGuard and IKEv2 are not available
Compatibility with legacy systems is required
PPTP needs to be replaced with something more secure
Temporary solution while planning modern protocol deployment

Need Help?

If you need assistance with L2TP/IPSec configuration:

Contact Support

Include your RouterOS version and specific error messages

Mikrotik L2TP/IPSec VPN Setup - Complete Configuration Guide