External Security Monitoring
The certificates, DNS, email security and uptime that customers and attackers can both see — watched continuously, so you know the moment something breaks or gets exposed.
The things that fail quietly are the ones customers see first.
Your domain, your certificates, your DNS records and your email security are all visible from the outside — and they're exactly the things that fail quietly. An expired certificate takes your website offline and throws security warnings at every visitor. A lapsed domain registration can hand your name to someone else. Missing or misconfigured email security (SPF, DKIM, DMARC) lets anyone send email pretending to be you.
The catch: most businesses only find out when a customer tells them. By then the damage — lost sales, blocked email, a spoofed invoice — is already done.
External Security Monitoring watches your public-facing surface around the clock and tells you before it becomes a problem.
Your whole public-facing surface, in one place.
SSL/TLS certificates
Expiry tracking with early warnings, certificate chain validity, and detection of weak or outdated encryption. No more surprise outages from a certificate nobody remembered to renew.
DNS & domain
Domain-expiry warnings, alerting on unexpected DNS record changes (an early sign of hijack or misconfiguration), nameserver health and DNSSEC status.
Email authentication
Continuous checks that your SPF, DKIM and DMARC records exist and are valid — the controls that stop criminals spoofing your domain and protect your deliverability.
Uptime & availability
Synthetic checks confirming your website and key services are actually up and responding, with alerting the moment they’re not.
Start with monitoring. Upgrade to fully managed.
Start with continuous monitoring. Upgrade to fully managed when you'd rather never think about it again.
Perimeter Watch Always-on monitoring. We tell you the moment something's wrong. Get a quote | Perimeter Managed Most popular Monitoring plus action. We find it, fix it, and keep it fixed. Get a quote | |
|---|---|---|
| SSL/TLS certificate monitoring | ||
| DNS & domain monitoring | ||
| Email authentication checks (SPF/DKIM/DMARC) | ||
| Uptime & availability monitoring | ||
| Monthly summary report | ||
| Certificate renewal handled for you | — | |
| DMARC enforcement journey (to p=reject) | — | |
| External vulnerability & attack-surface scanning | — | |
| Quarterly review call + written remediation plan | — | |
| Alerting | Yes | Yes, with response |
Priced per domain — no per-user charges. Get a quote for your domains and the tier that fits.
Managed Web Application Firewall (WAF)
Rule tuning and alert triage for businesses running public web applications.
Dark web & breach exposure monitoring
Alerts if your domain or staff credentials show up in known data breaches.
In-depth external security scan
Periodic, point-in-time deeper assessment of your internet-facing systems.
Several Cyber Essentials controls — secure configuration, boundary firewalls, and keeping internet-facing systems patched and properly configured — are evidenced by exactly the monitoring this service provides. If certification is on your roadmap, External Security Monitoring gives you a continuous, documented view of your perimeter and a natural first step towards getting certified.
Learn about Cyber EssentialsCommon questions
Will this slow down or interfere with my website?+
No. Monitoring is entirely external — we check your systems the same way a visitor would. Nothing is installed and there’s no impact on performance.
Do you need access to my systems?+
For monitoring (Perimeter Watch), no — everything is checked externally. For managed certificate renewal or DMARC enforcement (Perimeter Managed), we’ll agree the minimum access needed and document it.
What happens when something’s found?+
You’re alerted promptly. On Perimeter Watch we tell you what’s wrong and what we recommend. On Perimeter Managed, where it’s something we manage, we handle the fix.
Is this just for websites?+
No. As well as your website it covers your domain, DNS and email security — the things behind your email and online presence, not only the public site itself.
How is it priced?+
Per domain, as a simple fixed monthly fee — no per-user charges. Get in touch for a quote based on your domains and which tier suits you.
Find out what's exposed before someone else does
Get a free, no-obligation check of your certificates, DNS and email security — and a clear picture of where you stand.
Book a free perimeter checkBook your free perimeter check.
Tell me your domains and I'll come back within one working day with a clear picture of your certificates, DNS and email security — and a simple quote. No pressure, no jargon.