Outbound NAT, DMZ routing and packet-filter inspection are exactly the things an API-only integration cannot touch, and they are the things that break inter-VLAN traffic; here they run over SSH alongside the API tools, so a diagnosis and its fix happen in one session. Two things to weigh before pointing it at a live firewall: SSH access means shell execution on the box, so the credential you give it is as powerful as the account behind it, and the plan-then-apply and macro-recording paths are the safer way to make a multi-step change than issuing the calls one at a time and hoping.
A wide operations surface for an OPNsense firewall, working two ways: the OPNsense API for most configuration, and SSH into the box for the parts that need direct XML or shell access, such as outbound NAT and routing repair.
- Firewall rules created, listed, read, updated, toggled and deleted, with find_firewall_rules for locating one and create_firewall_preset for common shapes
- VLANs created, listed, read, updated and deleted, and interfaces listed, read and reconfigured — including inter-VLAN routing and DMZ setup
- NAT handled through its own family: port forwards and outbound rules created, listed and deleted, nat_get_mode and nat_set_mode switching between automatic, hybrid, manual and disabled, and nat_analyze_config plus nat_apply_changes around them
- Routing diagnostics and repair — routing_diagnostics, routing_create_intervlan_rules, routing_fix_dmz and routing_fix_all
- Network visibility: list_dhcp_leases, list_arp_entries with lookups by IP, MAC, hostname or interface, get_arp_stats, and device lookups by name, MAC, VLAN or interface, including get_guest_devices
- DNS blocklisting: block_domain and block_multiple_domains, unblock_domain, list and search the blocklist, toggle single entries, and subscribe to blocklist categories with add_dnsbl_subscription and apply_blocklist_category
- HAProxy managed in full — frontends, backends, servers, ACLs, actions and certificates created, updated and deleted, with haproxy_backend_health, haproxy_stats and haproxy_service_control
- ACME certificates signed, renewed, revoked and updated, with its own actions and settings
- Monit monitoring: services, tests and alerts added, updated and deleted, plus monit_status
- SSH and CLI execution for what the API will not do — ssh_execute, ssh_batch_execute, ssh_show_routing, ssh_show_pf_rules, ssh_system_status, ssh_reload_firewall and targeted fixes such as ssh_fix_dmz_routing
- Configuration backups created, listed and restored, with ssh_backup_config and ssh_restore_config as the shell-side equivalent
- Macros: start and stop recording a sequence of calls, replay it, export or import it, analyse it, and turn a recorded macro into a tool of its own
- An infrastructure-as-code path — iac_list_resource_types, iac_plan_deployment, iac_apply_deployment and iac_destroy_deployment — so a change can be planned before it is applied
- test_connection and configure for checking and setting up the connection itself
An OPNsense firewall — v24.7 or later recommended — and API credentials: OPNSENSE_HOST, OPNSENSE_API_KEY and OPNSENSE_API_SECRET, with OPNSENSE_VERIFY_SSL for self-signed certificates. Node.js 18+ or Bun 1.0+, installed as npm install -g opnsense-mcp-server. The SSH and CLI tools need separate access — OPNSENSE_SSH_HOST and OPNSENSE_SSH_USERNAME with either OPNSENSE_SSH_PASSWORD or OPNSENSE_SSH_KEY_PATH — and NAT management in particular runs through SSH rather than the API. MIT.
One command plus a key — npm install -g opnsense-mcp-server, then supply credentials