Setting up a client-accessible L2TP/IPsec VPN on a Cisco Meraki appliance gives organizations a familiar, broadly compatible remote access solution that integrates cleanly with Meraki’s cloud management. This article walks through a practical, step-by-step configuration for Meraki MX devices, explaining key technical considerations, best practices, and troubleshooting tips so webmasters, IT administrators, and developers can deploy a secure and reliable L2TP service quickly.

Why choose L2TP/IPsec on Meraki?

L2TP over IPsec remains widely supported by built-in OS clients across Windows, macOS, iOS and Android. On Meraki MX appliances, the client VPN feature simplifies deployment: no additional on-premises AAA servers are required for small-to-medium deployments, and integration with existing RADIUS or Active Directory is supported for enterprise-grade authentication. Key advantages include:

  • Native client support across platforms (reduces need for third-party clients).
  • Per-user authentication via local accounts or RADIUS/AD.
  • Centralized policy and logging through the Meraki Dashboard.
  • IPsec encryption for confidentiality paired with L2TP for session management.

Pre-deployment checklist

Before configuration, ensure the following prerequisites and design decisions are made:

  • Meraki MX device with a valid license and Dashboard access.
  • Public IP address assigned to the MX (or accessible via NAT/port forwarding if behind another device).
  • A plan for the client IP pool (non-overlapping with internal subnets and remote client networks).
  • Decide authentication method: local users, RADIUS, or Active Directory.
  • Firewall/NAT devices in front of the MX must allow UDP ports 500 and 4500, and IP protocol 50 (ESP) if NAT Traversal is not required. For typical NAT scenarios, ensure 500 and 4500 are open and that NAT-T is supported.
  • Pre-shared key (PSK) for IPsec — create a strong, unique PSK and store it securely.

Step-by-step configuration on Meraki Dashboard

All configuration is performed via the Meraki Dashboard (dashboard.meraki.com). The following steps assume you have organization and network admin privileges.

1) Navigate to the Client VPN settings

  • In the Dashboard, open the target network that contains the MX device.
  • Go to Security & SD-WAN > Configure > Client VPN.

2) Enable the Client VPN

  • Toggle Enable Client VPN to ON.
  • Choose the Client VPN server public IP: This can be the MX public IP or a hostname if you use a DNS entry that resolves to the MX.

3) Configure authentication and IP address pool

  • Authentication: Select one of the following:
    • Meraki Cloud (Local) — create local username/password accounts on the Dashboard.
    • RADIUS — configure your RADIUS server(s) with shared secret and mapping, recommended for enterprise environments.
    • Active Directory — via AD authentication through RADIUS or LDAP integrations.
  • Client IP address range: Enter a CIDR that does not overlap with any internal LAN or other remote networks (example: 192.168.100.0/24). Meraki will hand out addresses from this pool to connecting clients.

4) Configure IPsec parameters

  • Pre-shared key (PSK): Enter your PSK. This must be the same value provided to client devices.
  • DNS servers: Optionally specify internal DNS servers for name resolution of internal resources; otherwise, clients will use public DNS.
  • Split tunneling: Decide whether to send all traffic through the VPN (default secure option) or enable split tunneling. On Meraki, split tunneling is configured by defining local network subnets that should be reachable via the tunnel; other traffic will go out via the client’s local gateway.

5) Configure user accounts (if using local authentication)

  • Go to the same Client VPN page and add usernames and passwords for local authentication. Assign each account an email or description as needed. For RADIUS, ensure user accounts exist on the RADIUS/AD side.

6) Apply firewall and SD-WAN rules

  • Under Security & SD-WAN > Firewall, ensure rules allow traffic from the client IP subnet to internal resources you intend to expose.
  • Create inbound rules that limit VPN client access to only necessary internal subnets and services (e.g., allow RDP to jump host, SMB only to file server subnets, etc.).
  • Log and monitor connection attempts for security auditing.

Client configuration examples

Clients will configure an L2TP/IPsec VPN profile with the following typical parameters:

  • Server: MX public IP or hostname
  • Account/Username: local or AD account
  • Password: user password
  • Pre-Shared Key: PSK configured on the Meraki Dashboard
  • Type: L2TP/IPsec
  • Use secure communication or “Use IPsec” depending on client UI

On Windows, use the built-in Network > VPN > Add a VPN connection wizard. On macOS, create a new VPN in System Preferences > Network with L2TP over IPsec. On iOS, add a new VPN configuration under Settings > General > VPN > Add VPN Configuration.

Technical considerations and best practices

To ensure the setup is both secure and robust, follow these recommendations:

IP address planning

  • Choose a client pool in a separate subnet to avoid routing conflicts. Example: if internal network is 10.0.0.0/16, choose something like 192.168.254.0/24 for clients.
  • For environments with multiple VPN servers or remote sites, ensure no overlapping address spaces to avoid split-horizon issues.

Authentication and password policies

  • Prefer RADIUS with AD for centralized user management and accountability. Meraki supports RADIUS failover by providing multiple RADIUS servers.
  • Enforce strong password policies and consider multi-factor authentication (MFA) where possible — note that native L2TP/IPsec does not natively support MFA, but you can integrate MFA via RADIUS solutions that support it.

Security of the PSK

  • The PSK is shared among all L2TP clients when using PSK-based authentication. Use a long, high-entropy PSK and rotate it periodically. For per-user uniqueness, use RADIUS (username/password).

Port and protocol requirements

  • Open UDP 500 and UDP 4500 on any upstream firewalls. When NAT exists between client and server, NAT Traversal (UDP 4500) handles IPsec. Allow IP protocol 50 (ESP) if NAT traversal is not used.

Logging and monitoring

  • Enable event logging in the Meraki Dashboard and export logs to SIEM or external syslog for long-term retention.
  • Monitor authentication failures to detect brute-force attempts and anomalous patterns.

Troubleshooting common issues

Here are typical problems and how to diagnose them:

Clients cannot establish phase 1 (IKE) or phase 2 (IPsec) connections

  • Verify UDP 500 and UDP 4500 are reachable from the client to the MX public IP. Use tools like packet captures on edge firewalls or simple port checks (nc/nping).
  • Ensure the PSK matches exactly on both client and Meraki configuration (watch for trailing spaces).
  • Check for double NAT conditions that might block or alter IPsec traffic; ensure NAT-T is supported.

Clients authenticate but cannot reach internal resources

  • Check the client IP pool and ensure routing exists between that pool and the internal subnets. Add static routes if necessary.
  • Review MX firewall rules — ensure VPN clients are allowed to access the intended subnets/services.
  • Check DNS settings: if internal resource names do not resolve, configure internal DNS servers on the Client VPN settings.

Intermittent disconnects

  • Look for IPsec SA rekeying issues related to incompatible lifetimes. Meraki handles standard lifetimes, but third-party clients may have different defaults. Ensure client settings use defaults compatible with IPsec NAT-T.
  • Investigate noisy NAT devices or idle timeouts on upstream devices that may drop the UDP mappings — enable keepalives if supported.

Advanced topics

For organizations needing additional capabilities, consider these enhancements:

  • Use RADIUS with accounting to track session duration and bandwidth for auditing or billing.
  • Combine L2TP/IPsec with split tunneling to reduce bandwidth usage on the MX for high-traffic clients, but weigh the security implications.
  • For stronger security and modern crypto, consider deploying an SSL or IKEv2-based solution if you need features like native MFA or better mobility handling. Meraki also supports client VPN via third-party solutions when needed.

Deploying L2TP/IPsec on a Cisco Meraki MX can be a fast and effective way to provide remote access without third-party clients. Follow careful IP planning, secure authentication practices, and proper firewall/NAT configuration to ensure smooth operation. For a step-by-step start, configure the Client VPN on the Meraki Dashboard, choose an isolated client pool, secure the PSK, and integrate with RADIUS/AD if possible to scale securely.

For more detailed guides and device-specific examples, visit Dedicated-IP-VPN at https://dedicated-ip-vpn.com/.