Everything a business owner needs to know about domain names and DNS management to ensure website security and email deliverability.
Domain names and DNS are the foundation of your business’s online presence — and one of the most frequently mismanaged aspects of small business IT. Businesses lose control of their domains, experience email deliverability failures, and suffer website outages because nobody clearly owns the DNS management responsibility.
This guide explains what you need to know without unnecessary technical depth.
What a Domain Name Is
Your domain name (company.com.au, company.com) is your business’s address on the internet. When someone types it in a browser or sends you an email, the domain name system translates that name to the actual server address where your website or email service lives.
You do not own your domain name — you licence it for a defined period from a domain registrar, subject to renewal. If you fail to renew, the domain expires and can be registered by anyone else. Losing your domain means losing your website address and your email addresses.
Your domain registrar is the company where the domain is registered. Common Australian registrars: VentraIP, Crazy Domains, GoDaddy, Netfleet, Aussie Hosting.
What DNS Is
DNS (Domain Name System) is the phone book that translates domain names to the actual server addresses and configurations. DNS records control:
- Where your website is hosted (A record or CNAME pointing to your web host’s IP address)
- Where your email is delivered (MX records pointing to your email server — Exchange Online for Microsoft 365)
- Email authentication (SPF, DKIM, DMARC records — see below)
- Various other services (subdomain routing, domain verification for third-party services)
DNS records are typically managed at the registrar or at a dedicated DNS hosting service (Cloudflare, Amazon Route 53). Changes to DNS records propagate across the internet in minutes to 48 hours depending on the record’s TTL (Time to Live) setting.
The Most Critical DNS Records for Business Email
If these records are wrong, your business email has serious problems — either it does not deliver, or it is vulnerable to spoofing.
MX Records (Mail Exchange)
MX records tell the internet where to deliver email sent to your domain. For Microsoft 365:
@ MX 0 company-com.mail.protection.outlook.comIf MX records are wrong, inbound email stops being delivered. This is an emergency — recipients cannot reach you.
SPF Record (Sender Policy Framework)
SPF specifies which mail servers are authorised to send email from your domain. For Microsoft 365:
@ TXT v=spf1 include:spf.protection.outlook.com -allWithout SPF, your domain can be spoofed — attackers can send email that appears to come from your addresses.
DKIM Records
DKIM adds a cryptographic signature to outbound emails. For Microsoft 365, two CNAME records are required (provided by Microsoft when you enable DKIM in the Microsoft 365 admin centre).
Without DKIM, your emails may be flagged as suspicious by recipient mail servers, reducing deliverability.
DMARC Record
DMARC tells receiving mail servers what to do with emails that fail SPF or DKIM. Start with monitoring:
_dmarc TXT v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com.auProgressively move to p=quarantine and then p=reject as you confirm all legitimate email sources pass authentication.
The Most Common DNS Problems
Domain Expiry
Domains have annual or biennial renewal fees. If auto-renewal fails (expired credit card, changed email address on the registrar account) and manual renewal is missed, the domain expires.
Prevention:
- Enable auto-renewal with a valid payment method
- Use an email address on a different domain for registrar notifications (not the domain being renewed — if it expires, you lose the renewal notification too)
- Set a calendar reminder 90 days before renewal
- Ensure your IT provider has visibility of domain renewal dates
Accessing Your Registrar
Many businesses do not know who their registrar is or how to log in. This becomes a crisis when urgent DNS changes are needed (email authentication, SSL certificate renewal, website migration).
What to do now: Identify your domain registrar (use WHOIS lookup at whois.domaintools.com), confirm you have login credentials, and document them securely.
DNS Propagation Delays
When DNS records are changed, the change propagates globally over minutes to 48 hours depending on the TTL setting. During propagation, some users see the old record and others see the new one — which can cause confusing, intermittent issues.
Management: Use low TTL values (300-600 seconds) before planned changes, and increase TTL after changes are confirmed stable.
Incorrect Email Authentication Records
SPF, DKIM, and DMARC records are frequently missing, misconfigured, or outdated (not reflecting all authorised sending services). The result: reduced email deliverability and vulnerability to domain spoofing.
Test your records: Use MXToolbox (mxtoolbox.com) → Email Health Check. Enter your domain and review the results.
Who Should Own DNS Management
DNS is infrastructure — it needs to be owned by someone with clear accountability. Options:
IT Provider: Your managed IT provider manages DNS as part of your overall IT service. Changes are handled through a service request. This is the recommended approach for most Melbourne SMBs — DNS is technical and the consequences of errors are immediate and significant.
Internal IT staff: If you have an internal IT manager with DNS experience, they can manage DNS directly. Ensure they document all records and that credentials are held by the business, not the individual.
Business owner: For very small businesses, direct ownership of the registrar account is appropriate. Use a password manager to store credentials securely.
Whoever manages it: Ensure credentials are held by the business, not an individual who may leave. Ensure renewal notifications go to a monitored email address. Ensure changes are documented.
CX IT Services manages domain registration and DNS for Melbourne business clients as part of our managed IT service. Contact us to discuss domain and DNS management.
