Why smart TVs, printers, and cameras need their own network

TL;DR — Smart TVs, printers, cameras, speakers, and other "IoT" (internet-connected) devices are convenient but are usually the weakest security devices on your network. The single most useful fix is to put them on a separate network or Wi-Fi SSID (network name) that cannot freely reach your laptops, phones, servers, and shared files. Reading time: ~7 min

What it is and where it sits

Putting smart TVs, printers, and cameras on their own network is called network segmentation (splitting one network into smaller, controlled parts). In plain English: instead of every device in your office or home office living in one big room, you create a second room for the risky devices and lock the door between them.

In practice, that separate network is usually one of these:

• a second Wi-Fi network / SSID, such as Office-IoT
• a VLAN (virtual LAN; a logical network split on the same hardware)
• a dedicated "guest" network, if your router lets you block access to local devices

This sits at the network edge: your router, firewall, or Wi-Fi gateway decides which devices can talk to which other devices.

What talks to it:

• Smart devices talk out to the internet for updates, streaming, cloud control, and vendor apps.
• Your trusted devices — laptops, phones, tablets — may need limited access to some of them, such as printing to a printer or viewing a camera feed.
• Your router/firewall sits in the middle and enforces the rules.

What it replaces:

• The default "flat network" setup where every device can often see and talk to every other device.

Where it lives in a typical flow:

• Device joins the IoT network.
• Router gives it an IP address.
• Router allows internet access.
• Router blocks or limits access from IoT devices to your main network.

[Phone/Laptop] ---- 1. join Main Wi-Fi ----> [Main Network]
[TV/Printer/Camera] ---- 2. join IoT Wi-Fi ----> [IoT Network]
                         | 3. internet only
                         v
                      [Router/Firewall] ---- 4. allow updates/cloud ----> [Internet]
[IoT Network] ---- 5. blocked from reaching ----> [Main Network]
[Phone/Laptop] ---- 6. optional allowed access ----> [Printer]

The security idea is simple: if a camera gets hacked, or a printer is running old firmware (device software), the attacker lands in the IoT segment instead of next to your laptops, password managers, cloud admin sessions, and file shares.

How it actually works

The mechanism is not magic. Your router or firewall applies traffic rules based on which network a device is on.

Typical rules look like this:

• Main network → internet: allow
• IoT network → internet: allow
• IoT network → main network: block
• Main network → IoT network: block by default, then allow only what you need

One realistic example: office printer on an IoT network

Let’s walk through a common case: you have a Wi-Fi printer that staff need to print to, but you do not want that printer to have open access to employee laptops.

Step 1: Create two networks

You keep your normal Wi-Fi for people and create a second one for devices:

• Office-Main for laptops and phones
• Office-IoT for printer, TV, cameras

Your router gives them different IP ranges, for example:

• Main: 192.168.10.0/24
• IoT: 192.168.20.0/24

That means devices are now in different network segments.

Step 2: Put the printer on the IoT network

On the printer’s screen or web setup page, connect it to Office-IoT instead of the main Wi-Fi.

Now the printer can usually still:

• reach the internet for updates
• talk to its vendor cloud service if it uses one
• get an IP address from the router

But it is no longer sitting directly beside every laptop.

Step 3: Block IoT devices from initiating connections to the main network

This is the key rule. The printer should not be able to scan your laptops for open file shares, poke at your NAS (network attached storage), or reach internal admin tools.

So the router/firewall blocks traffic from 192.168.20.0/24 to 192.168.10.0/24.

Step 4: Add one narrow exception so staff can print

Your laptops still need to send print jobs to the printer. So instead of opening everything, you allow one-direction access from Main to the printer’s IP.

For example:

• allow 192.168.10.0/24 → 192.168.20.50 on printer ports
• keep 192.168.20.50 → 192.168.10.0/24 blocked

Now the flow is:

1. Employee laptop on Main sends a print job to printer on IoT.
2. Router allows that specific traffic.
3. Printer receives the job and prints.
4. If the printer is compromised, it still cannot freely roam into the Main network.

That is the whole pattern. Cameras, smart TVs, doorbells, speakers, and other appliances work the same way.

One catch: some devices rely on mDNS (multicast DNS; local device discovery) or similar discovery protocols, so they may not automatically appear across segments. That is normal. The fix is usually to add the device manually by IP address, use the vendor app’s cloud path, or enable a router feature that relays discovery traffic between networks if your equipment supports it.

When to use it (and when not to)

If you have more than a couple of internet-connected appliances, you should strongly consider this.

You probably don’t need this if...

• you have no IoT devices beyond maybe one basic printer
• your devices are already on a guest network with local access disabled
• your router cannot do any meaningful isolation and replacing it is not worth it for your setup

But for most small businesses, agencies, and home offices, this is one of the cleanest security improvements you can make without changing how people work day to day.

Trade-offs

Every security improvement costs something. Here is the honest version.

The biggest practical downside is convenience. Consumer devices are designed for "same Wi-Fi and auto-discover everything." Segmentation deliberately breaks that assumption. Usually that is worth it, but it does mean you may need to add a printer by IP address or use a streaming device’s app differently.

In practice

Below are practical examples you can adapt.

Example 1: Router dashboard setup checklist

This is the safest starting point because most people will use a router, firewall, or Wi-Fi controller UI rather than a command line.

Use your provider’s dashboard or router admin page. The exact labels vary, but look for paths like:

• Wi-Fi / Wireless → Add Network
• Networks / LAN / VLANs → Create Network
• Firewall / Access Rules → Add Rule
• DHCP / Address Reservation → Reserve IP

Create settings like this:

{
  "main_network": {
    "name": "Office-Main",
    "subnet": "192.168.10.0/24"
  },
  "iot_network": {
    "name": "Office-IoT",
    "subnet": "192.168.20.0/24",
    "client_isolation": true,
    "internet_access": true
  },
  "firewall_rules": [
    "block 192.168.20.0/24 -> 192.168.10.0/24",
    "allow 192.168.10.0/24 -> 192.168.20.50 tcp 9100,631,515"
  ]
}

What it does: this shows the target end state — separate subnets, internet access for IoT, blocked IoT-to-main access, and a narrow exception for one printer. Gotcha: many home routers offer a "guest network" but do not let you add exceptions back to a printer; if printing fails, you may need a router with real firewall rules or put only the printer on Main and move the rest of IoT devices off it.

Example 2: Linux firewall rules on a router using iptables

If your router runs Linux and supports custom firewall rules, this is the kind of policy you want.

⚠️ Firewall changes can cut off internet access or lock you out of the router until fixed. Save your current config first, and if possible make changes from a wired connection, not over Wi-Fi.

# Variables
MAIN_NET="192.168.10.0/24"
IOT_NET="192.168.20.0/24"
PRINTER_IP="192.168.20.50"

# Block IoT devices from reaching the main network
iptables -A FORWARD -s "$IOT_NET" -d "$MAIN_NET" -j DROP

# Allow main network to reach the printer on common printing ports
iptables -A FORWARD -s "$MAIN_NET" -d "$PRINTER_IP" -p tcp -m multiport --dports 9100,631,515 -j ACCEPT

# Allow IoT devices to reach the internet
iptables -A FORWARD -s "$IOT_NET" -o wan0 -j ACCEPT

What it does: blocks IoT-to-main traffic, allows staff devices to print to one printer, and still lets IoT devices reach the internet. Gotcha: interface names like wan0 vary; on your router it may be eth0, pppoe-wan, or something else, so check before pasting.

Example 3: Add a printer manually by IP on Windows or macOS

If printer discovery stops working after segmentation, add the printer directly.

Windows path:

• Settings → Bluetooth & devices → Printers & scanners → Add device → Add manually
• Choose Add a printer using an IP address or hostname
• Enter the reserved printer IP, for example 192.168.20.50

macOS path:

• System Settings → Printers & Scanners → Add Printer, Scanner, or Fax
• Click the IP tab
• Enter 192.168.20.50
• Protocol: usually HP Jetdirect - Socket or IPP

If you need the hostname instead of IP, it would look like this:

Address=192.168.20.50
Protocol=IPP
Queue=ipp/print
Name=Office Printer
Location=IoT Network

What it does: bypasses local discovery and points the computer straight at the printer. Gotcha: reserve the printer’s IP in the router first; otherwise the address can change and everyone’s printer setup breaks.

Further reading

• NIST SP 800-41, Guidelines on Firewalls and Firewall Policy
• NISTIR 8259, Foundational Cybersecurity Activities for IoT Device Manufacturers
• The "Securing Your Wi-Fi Network" guidance from your router vendor’s official docs
• The "Printing with IPP" sections in your printer vendor’s admin guide
• The "Multicast DNS" and "Service Discovery" sections of the MDN networking docs

This article was written by an AI system and published pending human review. Verify anything you intend to act on.