Service specification
Networks & Secure Connectivity
Design, deployment and continuous management of perimeter security, inter-site connectivity, remote access and wireless LAN.
Scope
The service covers all network components between the carrier demarcation point and the access port or SSID. It includes firewalls, VPN gateways, SD-WAN edges, switches, wireless controllers and access points, together with the associated licences, firmware and configuration.
- Site-to-site VPN between offices, data centres and cloud virtual networks.
- Remote-access VPN and zero trust network access (ZTNA) for home and mobile workers.
- Next-generation firewall policy, intrusion prevention, web and DNS filtering, TLS inspection.
- SD-WAN overlay with application-aware path selection across multiple circuits.
- Wired LAN segmentation and enterprise Wi-Fi with certificate-based authentication.
Out of scope: carrier circuits and their SLAs (we manage the supplier on the client's behalf), structured cabling installation, and operational technology (OT) controllers on the production side of the plant firewall.
Supported platforms
| Vendor | Product lines | Management plane | Typical deployment |
|---|---|---|---|
| Fortinet | FortiGate, FortiSwitch, FortiAP | FortiManager, FortiAnalyzer, FortiGate Cloud | Multi-site SD-WAN, single-vendor LAN edge |
| Palo Alto Networks | PA-400 and PA-1400 series, Prisma Access | Panorama, Strata Cloud Manager | Policy by App-ID and User-ID, regulated workloads |
| Sophos | Sophos Firewall XGS, APX access points | Sophos Central | Estates with Sophos endpoint (Synchronized Security) |
| WatchGuard | Firebox T and M series | WatchGuard Cloud | Single-site offices and branch deployments |
Devices must be under an active vendor support contract and running a release within the vendor's supported firmware train. End-of-support hardware is flagged in the assessment and scheduled for replacement.
VPN architecture
Site-to-site
Tunnels are route-based IPsec with IKEv2. Dynamic routing (BGP, or OSPF where required) runs over the tunnel interface so that failover does not depend on static routes. Hub-and-spoke is the default topology; full or partial mesh is used where inter-branch latency matters. Connections to Azure use VPN Gateway in active-active mode or a network virtual appliance in the hub virtual network.
| Parameter | Baseline value |
|---|---|
| Key exchange | IKEv2, certificate authentication (pre-shared key only by exception) |
| Encryption | AES-256-GCM |
| Integrity / PRF | SHA-384 |
| Diffie-Hellman group | 20 (ECP-384); 19 minimum |
| Perfect forward secrecy | Enabled, same group as phase 1 |
| Lifetimes | IKE SA 28 800 s; IPsec SA 3 600 s |
| Dead peer detection | 10 s interval, 3 retries |
Remote access
Remote users connect with an always-on client using IPsec/IKEv2 or a ZTNA agent. Authentication is federated to Microsoft Entra ID through SAML, so MFA and Conditional Access apply to the VPN in the same way as to cloud applications. Device posture (managed, encrypted, EDR healthy, patched) is checked before a session is established. Access is granted per application group, not to the whole internal network. Legacy SSL-VPN portals are migrated to IPsec or ZTNA during onboarding.
Firewall policy baseline
- Default deny between all zones; rules reference address objects and application signatures, not
any. - Separate zones for users, servers, voice, guest, IoT/printers, management and, where present, production equipment.
- Intrusion prevention and anti-malware profiles on all inter-zone and outbound flows.
- DNS and web filtering with blocking of newly registered domains and known command-and-control categories.
- TLS inspection for user traffic, with documented exclusions for banking, healthcare and certificate-pinned services.
- Administrative access restricted to the management zone, with MFA and named accounts; no management interface on the WAN.
- Geo-restriction of inbound services and outbound administrative protocols.
- Logs forwarded to a central collector, retained for a minimum of 12 months.
Rule bases are reviewed every six months. Unused rules (zero hit count over 90 days), shadowed rules and temporary rules past their expiry date are removed through change control.
SD-WAN
Each site is provisioned with at least two diverse underlays, typically FTTP or leased line as primary and a second fibre circuit or 5G as secondary. The SD-WAN edge measures latency, jitter and packet loss per path with active probes and steers traffic by application class.
| Traffic class | Examples | Path selection rule | Failover threshold |
|---|---|---|---|
| Real-time | Teams voice and video, SIP | Lowest jitter; forward error correction on lossy links | Latency >150 ms, jitter >30 ms, loss >1% |
| Business-critical | Practice management, ERP, RDP/AVD | Best quality, primary preferred | Latency >250 ms, loss >2% |
| SaaS | Microsoft 365, web applications | Local internet breakout | Path down |
| Bulk | Backup replication, updates | Secondary circuit, rate limited in business hours | Path down |
Wireless LAN
Wireless designs start with a predictive survey from floor plans and are validated on site after installation. Corporate SSIDs use WPA3-Enterprise with 802.1X and EAP-TLS; device certificates are issued through Intune so that no user enters a password to join the network. Guest access is isolated in its own VLAN with client isolation and a bandwidth limit. Access points are Wi-Fi 6 or 6E, with 20 or 40 MHz channels at 5 GHz in dense offices and minimum data rates raised to remove legacy 802.11b clients.
| Design target | Value |
|---|---|
| Primary coverage | −65 dBm or better at 5 GHz |
| Signal-to-noise ratio | 25 dB minimum |
| Co-channel overlap | No more than 2 APs above −82 dBm on one channel |
| Roaming | 802.11k/v/r enabled on corporate SSIDs |
Operations and deliverables
- Monitoring of device health, interface state, tunnel status, circuit quality and licence expiry, polled at 60-second intervals.
- Nightly configuration backup with version history and diff on change.
- Firmware lifecycle: security releases assessed within 5 business days of publication; critical vulnerabilities on internet-facing devices patched within 72 hours.
- Deliverables at handover: layer 2 and layer 3 diagrams, IP address plan, VLAN and zone matrix, firewall rule export, wireless survey report.
- Monthly report: availability per site, circuit performance, blocked threats, changes implemented.
Pricing
| Item | Unit | Indicative price |
|---|---|---|
| Managed firewall | Per device, per month | from £95 |
| Managed SD-WAN site | Per site, per month (includes edge firewall) | from £140 |
| Managed switch | Per device, per month | £12 |
| Managed access point | Per device, per month | £8 |
| Remote access / ZTNA | Per user, per month | £4 |
| Site-to-site VPN implementation | Per tunnel pair, one-off | from £450 |
| Wireless survey and design | Per floor up to 1 000 m², one-off | from £600 |
Prices are indicative, in pounds sterling and exclusive of VAT and local taxes; quotations are also issued in euros and US dollars. Hardware, vendor licences and carrier circuits are quoted separately at cost plus procurement handling. Minimum term 12 months.