Why Is Our Internet Slow?

A slow office internet connection is one of five things: the plan you buy from the provider, the firewall or router it comes through, the Wi-Fi, the wiring and switches, or a device on the network misbehaving, and a few minutes of testing tells you which. This article, first published in 2024 and updated in September 2026 with our older pieces on slow networks and the cost of poor connectivity folded in, walks through the diagnosis in order and what fixes each cause.

Test in the right order

Plug a laptop into the firewall or the provider’s modem with a cable and run a speed test. That number is what you are paying for. Now test from a desk over a cable, then over Wi-Fi. Each step that drops sharply points at the layer in between. Note the upload figure as well as the download, and test at a busy time and a quiet one. If everything is fine on a cable and bad on Wi-Fi, the problem is wireless; if it is bad everywhere, look at the connection and the firewall.

1. The plan itself

If the provider sells you 100 Mbps, nothing inside the office will ever be faster than 100 Mbps, and on many cable plans the upload is a small fraction of that. Upload is what video calls, cloud phone systems and cloud file sync depend on, and ten people on Teams calls can fill an older connection’s upload entirely. Fiber, where it is available, gives equal speeds in both directions and is often no more expensive than what businesses are paying for cable. We work with the Twin Cities providers and can usually find a faster plan for the same money, or the same plan for less.

2. The firewall or router

A consumer router bought for under a hundred dollars is not built for an office, and even a business firewall has a throughput limit that drops sharply when its security features, intrusion prevention, content filtering and VPN, are turned on. A firewall bought for a 50 Mbps connection will bottleneck a 500 Mbps one. Check the rated throughput with security enabled, and replace equipment older than about five years; it also stops receiving security updates around then.

3. Wi-Fi

One router in a corner serving thirty people is the most common cause of slow Wi-Fi. Fix it with business access points, placed centrally and high, enough of them to cover the space, managed together so devices roam between them. Use the 5 GHz band, and the 6 GHz band on Wi-Fi 6E and Wi-Fi 7 equipment, rather than the crowded 2.4 GHz band; modern access points handle dozens of devices each where older ones struggled with ten. Keep guests on a separate network. Our guide to securing your wireless network covers the security side of the same setup.

4. Wiring and switches

Cable that was run twenty years ago, terminated by whoever was handy, or stretched past its length limit will drop connections and speeds. A cheap unmanaged switch under a desk, daisy-chained from another, adds another bottleneck. A loop, two ports on the same switch connected to each other, can bring a whole office to a crawl within seconds and is surprisingly common after an office move. The baseline is Cat5e or Cat6 cable properly terminated, a managed switch in the rack with power over Ethernet for phones and access points, and no switches under desks.

5. DNS

Every web page starts with a DNS lookup, and a slow or failing DNS server makes a fast connection feel slow: pages hesitate before loading, then arrive all at once. Point the firewall at reliable resolvers and make sure an on-site server that provides DNS is healthy.

6. A device on the network

A computer with malware sending spam, a compromised server, a cloud backup running at noon, or a security camera system streaming to the internet can consume the whole connection. If slowness arrived suddenly with no other change, look for a device using unusual bandwidth; a managed firewall shows this immediately. Our guide to why a computer is slow covers the case where it is one machine rather than the network.

What a poor connection costs

When the connection is slow or down, the phones are down if they are cloud-based, cloud software stops, remote staff lose access to everything and the office reverts to waiting. For most businesses today that is a complete stop, not an inconvenience. Businesses that cannot afford it add a second connection from a different provider or a cellular failover on the firewall, so an outage becomes a slowdown. Quality-of-service settings on the firewall keep phone calls clear when the connection is busy. Our network support service designs and maintains all of this, and the phone systems quote tool shows what a cloud phone system needs from the connection. Under a managed plan, the firewall, switches and access points are monitored, so slowdowns are usually diagnosed before anyone calls.

Common questions

How do I tell whether the problem is the internet connection or our network?

Run a speed test from a computer plugged directly into the firewall with a cable, then from a desk over cable, then over Wi-Fi. If the first is slow, it is the connection or the firewall; if only the later ones are slow, it is your wiring, switches or Wi-Fi.

What internet speed does a small office need?

For most offices, 100 Mbps or more with an upload speed of at least 20 Mbps, and fiber where it is available. Upload matters more than people expect: video calls, cloud phones and cloud file sync all send as much as they receive. Ten people on Teams calls can saturate an old cable connection’s upload.

Why is our Wi-Fi slow when the internet test is fine?

Usually a consumer-grade router serving a whole office, too few access points, poor placement, or crowded channels. Business access points on the 5 GHz and 6 GHz bands, placed centrally and managed together, fix most of it. Wi-Fi 6 and later equipment handles many devices far better than the previous generation.

Can old wiring slow down the network?

Yes. Damaged or badly terminated cable, runs over the length limit, an old unmanaged switch, or a loop where two ports were plugged into each other can cut speeds or take the whole network down. Cat5e or better, properly terminated, is the baseline.

Could a slow connection be a security problem?

Yes. A computer infected with malware, or a compromised device sending spam or mining cryptocurrency, can consume the connection. If slowness appeared suddenly with no other change, check for that first.

What happens to the business when the internet goes down?

With cloud phones, cloud software and remote staff, everything stops. Businesses that cannot afford that add a second connection from a different provider, or a cellular failover on the firewall, so an outage becomes a slowdown instead.

Talk to us

Call 952-548-5558 or contact us; the first conversation is free and there is no long-term contract.