What happens to your business when your firewall fails?

Not your computers. Not your files. Just the one device that sits between your office and the internet.

For most small and midsized businesses, the honest answer is: everything stops. No email. No Microsoft 365. No cloud applications. No remote access.

That's the problem IT infrastructure redundancy solves.

We saw it firsthand with a client whose firewall went down. There was no second firewall to take over, so for about an hour, while our team restored it, the business was effectively offline.

And the firewall is only one example. Most businesses have several devices just like it: one server, one domain controller, one internet connection, each quietly holding up everything around it.

We've written before about backup redundancy and about the risk of depending on one IT person. This article looks at the rest of your environment: the firewalls, domain controllers, servers, storage, internet connections, and power your business runs on every day.

What Is IT Infrastructure Redundancy?

IT infrastructure redundancy means designing your technology so that no single device, connection, or system can stop your business when it fails. Critical components have a second component, path, or copy ready to take over, often automatically.

A single point of failure is the opposite: one component that, if it fails, takes everything that depends on it down too.

Redundancy is not the same as backup. A backup helps you recover after something goes wrong. Redundancy helps you keep working while it's going wrong. A resilient business needs both.

Single Points of Failure Don't Fail "If" They Fail "When"

Every piece of hardware has a lifespan. Power supplies burn out. Drives wear down. Firmware updates go sideways. Storms knock out power. A construction crew cuts a fiber line down the street.

A single point of failure isn't a risk that might show up someday. Given enough time, it will fail. The only questions are when, and what it costs your business when it does.

The cost is real. In the Uptime Institute's 2026 Annual Outage Analysis, 57% of organizations said their most recent major outage cost more than $100,000, and one in five said it cost more than $1 million.

Those figures come largely from larger organizations. But the pattern holds for a 25-person office too: when the systems stop, the business stops.

Here are the single points of failure we find most often, and what to do about each one.

Firewalls: The Front Door Everyone Walks Through

Your firewall sits between your network and the internet. Every email, website, cloud application, VPN connection, and often every phone call passes through it.

That makes it one of the most critical single points of failure in a typical small or midsized business. When it fails, you don't just lose security. You lose connectivity.

The solution is a high availability (HA) firewall pair: two firewalls configured to act as one. WatchGuard calls this FireCluster.

• In an active/passive cluster, one firewall handles all traffic while the second monitors it and takes over if the first fails.

• In an active/active cluster, both firewalls share the load, and either can carry it alone.

When a cluster member fails, many connections, including standard traffic and site-to-site VPN tunnels, carry over to the surviving firewall. Some, such as mobile VPN sessions, may need to reconnect. Either way, for a business like the client we mentioned above, an hour offline becomes a brief interruption.

As a WatchGuard provider, EMCO Technology designs and manages firewall clusters as part of our network services and cybersecurity work.

Domain Controllers: The Login Behind Every Login

If your business uses Active Directory, your domain controller (DC) is the system that verifies who your users are. It handles logins, permissions to shared folders, group policies, and often DNS, the service that lets computers find each other.

Many small businesses have exactly one.

Microsoft's guidance is direct: every domain should have at least two functioning domain controllers for fault tolerance. If the only domain controller fails, Microsoft notes, users "will not be able to log in to the domain or access domain resources."

And because the DC often provides DNS, a failure can ripple outward. Computers may struggle to reach file shares, printers, line-of-business applications, and sometimes the internet.

A second domain controller, ideally on separate hardware, keeps a synchronized copy of your directory. If one goes offline, the other keeps signing users in. One caution: changes and mistakes replicate too, so a second DC protects you from a hardware failure, not from the need for good backups.

Application Servers: When One Server Runs the Whole Business

Many businesses run their most important software on a single physical server: accounting, practice management, a database, an ERP system, or a license server for engineering software.

When that server fails, the application goes down with it. Restoring from backup can take hours or days, especially if replacement hardware has to be ordered first.

There are better options:

• Virtualization runs servers as virtual machines, so they no longer depend on one specific piece of hardware.

• Clustered hosts share the workload. If one host fails, its virtual machines restart on another.

• Hosted infrastructure moves critical servers into a data center built for uptime, with redundant power, cooling, and connectivity.

EMCO's Cloud and Virtual Services and Data Center services are built around this approach.

Storage: Where Every File Lives

File servers and network attached storage (NAS) devices hold the files your team opens all day. A single storage device is a single point of failure, no matter how much data it holds.

RAID spreads data across multiple drives so that one failed drive doesn't take your files offline. But RAID protects against a drive failing, not the whole device failing. A dead power supply, controller, or motherboard still takes everything offline.

For critical storage, consider replication to a second device or location, or cloud storage with built-in redundancy.

And remember: RAID and replication are not backups. If ransomware encrypts a file, replication copies the encrypted version within seconds. Redundancy keeps you running; backups let you recover.

Internet Connectivity: Your Link to the Cloud

The more your business moves to the cloud, the more it depends on one thing: the internet connection. Microsoft 365, VoIP phones, cloud applications, and remote access all stop when the internet does.

That dependency is often outside your control. Uptime Institute's 2025 analysis found that third-party providers, including cloud, internet, and telecom companies, account for about two-thirds of publicly reported outages.

You can't control your internet provider. You can control whether you depend on only one.

Dual-WAN failover adds a second internet connection from a different provider, ideally over a different physical path, such as fiber plus cable, or a cellular backup. Your firewall watches both. If the primary connection drops, traffic shifts to the backup automatically.

Power: The Most Common Cause of Outages

Power is the leading cause of impactful outages, according to the Uptime Institute. In a small office, that usually means a flicker, a brownout, or a summer storm.

Even a two-second power blip can reboot a server mid-write, corrupt data, or damage equipment.

Power redundancy can include:

• An uninterruptible power supply (UPS) sized for your critical equipment, so it can ride through short outages and shut down safely during long ones

• Dual power supplies in servers and switches, connected to separate circuits

• A generator for businesses that can't afford to close during an extended outage

The National Institute of Standards and Technology (NIST) lists UPS systems and generators among the preventive controls every contingency plan should consider.

Don't Forget the Network in Between

Switches, wireless access points, and cabling connect everything else on this list. If every device plugs into one core switch, that switch is a single point of failure.

Stacked switches, redundant links between them, and spare hardware on hand can turn a switch failure from a business-wide outage into a quick swap.

Redundancy Doesn't Mean Buying Two of Everything

This is where many businesses get stuck. Redundancy sounds expensive, so it gets postponed.

But redundancy isn't about duplicating your entire environment. It's about protecting the systems your business can't operate without.

The right level depends on what downtime actually costs you. A five-person office may only need a UPS and a backup internet connection. A law firm facing court deadlines or a manufacturer running a production line may need every row on this table.

At EMCO Technology, we believe in Intentionality: delivering the right technology at the right time, scaled to fit both your current and future needs. As your IT partner, we help you answer the question honestly. What truly needs redundancy? What can tolerate a short outage? And what simply isn't worth the investment?

That planning is a core part of our Fractional CIO/CTO services and our managed IT services.

How to Find the Single Points of Failure in Your Business

You don't need a data center to start. Walk through these steps:

1. List your critical business functions. Email, phones, file access, accounting, and your line-of-business applications.

2. Trace what each one depends on. Hardware, connections, accounts, and vendors.

3. Ask "what happens if this fails?" for every component. If the answer is "everything stops," you've found a single point of failure.

4. Estimate what an hour of downtime costs. Count idle employees, lost revenue, and the impact on clients.

5. Prioritize. Start where the cost of an outage is highest and the fix is simplest.

6. Test your failover. Redundancy that has never been tested is an assumption, not a plan.

7. Monitor both halves. If one firewall in a pair quietly fails and nobody is alerted, you're back to a single point of failure without knowing it.

IT Infrastructure Redundancy FAQs

What is a single point of failure in IT?

A single point of failure is any one component, such as a firewall, server, internet connection, or person, whose failure stops the systems that depend on it. Eliminating single points of failure means giving critical components a backup path or partner.

Is redundancy the same as backup?

No. Redundancy keeps your business running when a component fails. Backups let you restore data after it's lost, corrupted, or encrypted by ransomware. Redundancy does not protect against deleted or encrypted files, so most businesses need both.

Do small businesses really need a redundant firewall?

If your business depends on internet access, cloud applications, or remote access to operate, a firewall failure stops all of it. For many small businesses, a high availability firewall pair is one of the most valuable redundancy investments they can make.

How many domain controllers does a business need?

Microsoft recommends at least two functioning domain controllers per domain, so users can still sign in if one fails. Larger or multi-site businesses may need more.

How much does IT infrastructure redundancy cost?

It depends on which systems you protect. A UPS or a backup internet connection is a modest monthly or one-time cost. Clustered servers cost more. The right comparison is what a few hours of downtime would cost your business.

Your Business Shouldn't Stop Because One Device Did

For 25 years, EMCO Technology has helped businesses throughout the Greater Philadelphia region build technology that keeps running when something goes wrong.

We design high availability firewalls, redundant domain controllers, virtualized and clustered servers, resilient storage, failover internet, and power protection. More importantly, we help you decide which of those your business actually needs.

If you're not sure where the single points of failure are in your environment, let's find them before they find you. Talk with our team about a redundancy review.

A single point of failure will fail. The only question is whether your business goes down with it.