Sophos: How to harden AAA (TACACS+ / RADIUS) authentication

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30

What this guide covers

How to harden AAA (TACACS+ / RADIUS) authentication on Sophos devices (SFOS (Sophos Firewall OS)).

Recommendation

Centralise auth via TACACS+ / RADIUS, but always keep a local fallback in case the AAA server is unreachable.

CLI / commands

# Entered from: system configuration
system interface add name=Port1 ipv4-address=10.0.0.1 netmask=255.255.255.0 zone=LAN

# Save / commit
(auto-saves in Web UI; CLI changes persist)

Verify

• Test from a non-admin workstation.
• Confirm fallback works if AAA or external service is down.
• Document the change in your CMDB / change-control.

Frequently asked questions

Will this work on my specific SFOS (Sophos Firewall OS) version?

The procedure reflects current SFOS (Sophos Firewall OS) behaviour. Older releases may need minor syntax adjustments, use the CLI help (? or tab-completion) to verify.

Should I open a Sophos Support case immediately?

Open one if you suspect hardware failure or the symptom persists after a maintenance-window reload. Make sure your support entitlement is active first.

Where can I find the Sophos official documentation?

https://support.sophos.com/support/s/: search the product family + feature name.

Is this procedure safe in production?

Test in a lab or maintenance window first. Capture pre-change state so you can roll back.

Related guides

• All Sophos fix guides → /sophos/
• All vendor guides → /vendors/

Related fixes

Related guides worth a look while you sort this one out:

• Sophos: How to configure logging to a central SIEM
• Sophos: How to disable unused services and protocols
• Sophos: How to enable control-plane policing / rate-limiting
• Sophos: How to enable HTTPS-only management
• Sophos: How to enable management ACL to lock down access
• Sophos: How to enable NETCONF or vendor API over SSH

References

• Sophos support portal: https://support.sophos.com
• Sophos knowledge base: https://support.sophos.com/support/s/
• Sophos security advisories: https://www.sophos.com/en-us/security-advisories
• Open a case: https://secure2.sophos.com/en-us/support.aspx

Reference material, not professional advice. Validate against your specific SFOS (Sophos Firewall OS) version and test in a non-production environment before applying.

What changed recently?

Fault diagnosis on a Sophos: device goes faster when you map the symptom to a recent change:

• Did firmware update in the last 7 days?
• Did the network (router, ISP, VPN) change?
• Was the device moved physically?
• Did paired devices (phone, hub, app) update?
• Were any accessories swapped in or out?

The answer narrows the root cause to a manageable subset.

Before you start

A few things to confirm so the Sophos: device fix goes cleanly:

• Latest firmware downloaded if you're going to update.
• Warranty + support contract status checked, opening sealed parts may void it.
• Backup of current configuration (where applicable) taken.
• Spare parts on hand if you anticipate replacement.
• Adequate workspace, lighting, and time. rushing causes regressions.

How to confirm it's actually fixed

On a Sophos: device, the test is rarely "reboot and see". Use this list:

• Active reproduction: trigger the original failure path on purpose.
• Indirect reproduction: do an activity that would expose the same subsystem.
• Status indicator review: every LED / display / app status should be green.
• 24-hour soak: leave the device under normal load overnight; check the next morning.
• Telemetry check: review the device or app's diagnostic log for new error entries.

When to call Sophos: support instead

Escalate if:

• The same symptom returns within 24 hours of a clean fix.
• You see physical damage (burn marks, swollen battery, cracked PCB).
• The device is in warranty and a hardware replacement is the cheaper outcome.
• Repair requires specialised tools you don't own (alignment jigs, calibration software).
• Following the official path keeps the warranty intact, which matters more than the time spent.

More frequently asked questions

Will the procedure work on the international variant?

Some features and firmware paths are region-locked. Check the model spec sheet to confirm your variant supports the menu option referenced. If you're outside the US/EU, look for the regional support portal.

How long does this fix usually take?

Most users complete the steps in 20-45 minutes the first time, and 5-10 minutes on subsequent runs once the menu paths are familiar.

Are there safer alternatives for non-technical users?

Yes, the manufacturer's self-service troubleshooter (HP Smart, LG ThinQ, Samsung Members, similar) usually walks through the same steps in a guided UI. Use that first if you're not comfortable with menu paths.

What if my model isn't exactly the same revision?

Cross-check the model code on the rating plate against the manufacturer support page. Major firmware generations sometimes shift the menu path; the option is usually under a similarly-named section.

What if the fix returns after a reboot?

Persistent fault returns mean either: a hardware fault (escalate), a configuration that's being overwritten by a sync source (check cloud profiles), or a regression in a recent firmware update (rollback).