What Is an SSL Certificate? A Beginner’s Guide

HTTPS protects data in transit

An SSL certificate lets a browser verify the website name and create an encrypted HTTPS connection

Modern connections actually use TLS, but most people still call the certificate SSL. It protects data travelling between the visitor and the server. It does not prove that every claim on the website is trustworthy or that the site has no other security weaknesses.

ENCRYPTSData in transitBetween browser and server
VERIFIESThe website nameAgainst the certificate
RENEWSBefore expiryTo avoid browser warnings

How does an SSL certificate create HTTPS?

  1. 1
    The browser requests HTTPS

    A visitor opens an address beginning with https:// and contacts the web server.

  2. 2
    The server presents a certificate

    The browser checks the covered hostnames, issuing authority, validity period and certificate chain.

  3. 3
    An encrypted session begins

    If the checks pass, the browser and server agree secure connection keys and exchange the page over TLS.

What does HTTPS protect, and what does it not protect?

Protects

Data while it travels

Encryption makes it much harder for somebody on the network path to read or alter forms, logins and page content in transit.

Protects

Connection to the named site

The browser checks that the certificate covers the hostname being opened and chains to a trusted certificate authority.

Does not prove

The business is honest

A valid certificate does not make an offer, seller or download trustworthy. Scam and compromised sites can also use HTTPS.

Does not replace

Website security and maintenance

Passwords, updates, backups, malware protection, access controls and safe code remain necessary after HTTPS is working.

Why should every business website use HTTPS?

Protect forms and logins

Contact details, passwords and other submitted information should not travel over an unencrypted HTTP connection.

Avoid browser warnings

Browsers clearly warn visitors when a connection is insecure, a certificate has expired or the hostname does not match.

Use modern web features

Many browser capabilities and third-party integrations require a secure context before they will operate normally.

Provide the expected standard

Customers expect HTTPS on ordinary information sites as well as shops, account areas and payment journeys.

Which SSL route applies to a UKC service?

ServiceSSL routeImportant detail
UKC shared web hostingFree Let’s Encrypt SSL is available in PleskIssue it for the website names you use, enable renewal and redirect HTTP to HTTPS after testing
UKC parked domainDomain Parking SSL is a paid domain add-onIt secures the parked website and protects forwarding; it is normally provisioned automatically within a few minutes
Another hosting providerUse the certificate route supported by that platformThe certificate must be installed where HTTPS terminates, not simply purchased from the domain registrar
Cloudflare or another proxyConfigure both visitor-side and origin-side encryption correctlyA proxy certificate alone does not justify sending traffic to an insecure or unverified origin

Which names must the certificate cover?

A certificate is valid only for the hostnames listed in it. Cover every public name that should open securely, and avoid redirecting visitors through an uncovered name.

Root domain

example.uk is a different certificate name from www.example.uk. Include both if the website accepts both.

Subdomains

shop.example.uk, portal.example.uk and other services need explicit coverage unless a suitable wildcard certificate is used.

Mail hostnames

Email certificate warnings concern the hostname entered in the mail app. UKC shared-hosting customers should use their assigned server hostname.

Webmail hostnames

Use the supported secure webmail address. Creating a webmail subdomain does not automatically guarantee its certificate covers that name.

How should you install or enable HTTPS safely?

  1. 1
    Point DNS to the correct service

    The certificate authority must be able to validate the relevant hostname through the supported method.

  2. 2
    Issue the certificate

    Use the Plesk, parking add-on or external-platform process that controls the server receiving HTTPS.

  3. 3
    Test every important name

    Open the root domain, www name and any required subdomains directly over HTTPS.

  4. 4
    Redirect HTTP after testing

    Send visitors to the preferred HTTPS address only when that address works without certificate or content errors.

  5. 5
    Fix mixed content

    Update images, scripts, fonts and styles that still load from insecure http:// addresses.

  6. 6
    Confirm renewal

    Automatic renewal still depends on working validation, DNS and service configuration. Investigate renewal warnings promptly.

What causes common certificate warnings?

WarningLikely causeWhat to check
Name mismatchThe opened hostname is not listed in the certificateUse a covered hostname or reissue the certificate with every required name
Expired certificateRenewal failed or the replacement is not installed on the active serviceCheck expiry, renewal logs, DNS validation and which server answers the request
Untrusted issuer or chainThe browser cannot build a trusted chain to the issuing authorityInstall the correct certificate and intermediate chain on the server
Mixed contentThe page is HTTPS but an image, script or other resource still uses HTTPUse browser developer tools or a site scan to locate and update insecure resource URLs
Wrong website shownDNS, a proxy or the server virtual host points to the wrong destinationTrace DNS and confirm the hostname is attached to the intended hosting account

Use the UKC SSL checking guide

SSL certificate questions

What is the difference between SSL and TLS?

SSL is the older protocol name that remains common in product language. Secure websites now use TLS, while the certificate is still widely called an SSL certificate.

Does a certificate make a website completely secure?

No. It protects the connection in transit. The website, server, accounts, software and business processes still need their own security controls.

Is free SSL included with UKC hosting?

Yes. Current UKC shared-hosting plans provide Let’s Encrypt SSL through Plesk.

Can I use free hosting SSL on a parked domain?

A parked domain is a different service. Use the Domain Parking SSL add-on to secure the parked website and forwarding.

Will HTTPS automatically improve rankings?

HTTPS is an expected technical foundation, not a substitute for useful content, relevance, accessibility and a good customer experience. Do not buy a certificate based on a guaranteed ranking claim.

Why is the padlock not proof that a site is genuine?

The certificate proves control of a hostname and protects the connection. It does not verify every business claim, product or person behind the site.

Make HTTPS part of the service

Choose hosting with SSL included, then verify the names, redirect and renewal

UKC shared hosting includes Let’s Encrypt SSL. Parked domains can add Domain Parking SSL from their domain tools.

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