About TCP123 UK & Domain Shield
Domain Shield is a free email security scanner built and run by TCP123 UK, a UK IT support business serving small and medium-sized companies. Enter a domain and the tool audits its SPF, DKIM and DMARC records, scores the result 0–100, and explains the fixes in plain English.
How it is funded
The scanner is free and always will be. TCP123 UK earns revenue from paid email and DNS remediation work: if your report shows gaps you would rather have handled for you, the fix plan links to our paid service. There is no obligation, and the scan itself never touches your systems.
What the scanner does — and does not do
Every scan reads public DNS records only. We never ask for passwords, never access mailboxes, and never change anything on your domain. Scan queries are not logged against your identity, and anonymous analytics run only with your consent. Full details are in our privacy policy.
Company details
| Trading name | TCP123 UK |
|---|---|
| Registered company name | [REGISTERED NAME — OWNER TO SUPPLY] |
| Company number | [COMPANY NUMBER — OWNER TO SUPPLY] |
| Registered address | [REGISTERED ADDRESS — OWNER TO SUPPLY] |
| Contact | support-team@tcp123.uk |
| Website | tcp123.com · tcp123.uk |
Placeholders above are completed by the site owner before go-live (tracked as task #6 in docs/TASKS.md).