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Why Router vs Firewall Really Only Matters at Work

Routers and firewalls are network security devices, sometimes grouped into business and home network packages or sold separately as dedicated hardware.

Though the two are closely linked, routers and firewalls are very different devices.

  • Router: Exchanges data between networks or gateways.
  • Firewall: Blocks traffic from protected networks.

Put simply, routers connect networks and move data efficiently, while firewalls protect networks by controlling and securing the flow of data.

For home networks, most people already have a router with a built-in firewall. Under normal circumstances, they don’t need to get an extra firewall to keep their network safe.

Businesses, on the other hand, typically have more than one router and benefit from having a discrete firewall device or application. Thoughtful deployment of both elements is an important part of securing a business network.

Key differences between routers and firewalls

Here is a quick breakdown of the key differences between routers and firewalls:

Network Role: Routers and firewalls serve different purposes in a network. A router connects networks and ensures data travels efficiently between them, like a VoIP router for voice traffic. A firewall, on the other hand, is like a security checkpoint, inspecting and filtering data to block potential threats.

Traffic Management: Routers focus on directing traffic based on IP addresses, determining the best path for data to reach its destination. Firewalls control traffic by applying security rules, deciding what data is allowed to pass through or be blocked based on factors like source, destination, and content.

Default Behavior: By default, routers allow all data to pass unless specific restrictions are added. Firewalls take the opposite approach: they block most traffic unless explicitly allowed, prioritizing security over openness.

Placement: Routers are typically positioned at the edge of the network to connect it to the internet or other networks. Firewalls can be placed at the edge or internally within the network to control access between segments, adding extra layers of protection.

Customization and Control: Firewalls are built for granular control, letting you enforce security policies based on specific applications, users, or behaviors. Routers, while configurable, prioritize speed and efficiency over detailed filtering.

Why router vs firewall doesn’t matter on a home network

Most routers have a built-in firewall that offers basic protection for homes and very small offices. Typically it is a stateful firewall capable of inspecting traffic flows and performing basic perimeter security.

Because the router already has a firewall installed, the average home network does not need a separate or additional firewall. These simple networks tend to have a handful of devices connected to a single router, and the integrated firewall is enough to keep the network safe from unwanted traffic and prevent unauthorized users from gaining access to the network.

On top of this, modern devices have built-in firewalls of their own. Windows Defender and Android Firewall are two common examples.

From the moment your ISP turns on the internet at your house, every device connected to the router is already shielded from the public internet by multiple firewalls.

If you are doing something out of the ordinary at home — like running a business with sensitive information or hosting a game server — more advanced software or hardware firewall protections will be important to set up.

People with a lot of IoT (Internet of Things) devices on a home network might also consider additional firewall protections as one of the ways to reduce IoT attack surface.

But outside the edge-cases, you really don’t have to compare router versus firewall at all — you probably have both already.

Why router vs firewall matters a lot for business

On business networks, tons of devices are logging in and out constantly, using cloud applications and potentially connecting to offices at other locations over a Wide Area Network (WAN).

Unlike simple home networks, business networks have multiple routers (and a host of other elements) that connect physical and virtual resources to users. Routers play a key role in setting up an effective network security architecture, and while they may have built-in firewall functionality, businesses most often have dedicated hardware and/or software firewalls.

Organizations need to protect their connected devices from virus and malware threats, but also from sophisticated security concerns that would never impact a home network.

Business-grade firewalls offer granular control over the traffic, which means that managers can regulate access separately for different users and applications. This is important when you have protected resources on the network that you need to make available to the public, remote workers, or third-parties.

This access control is centralized in a business’s firewall security policy, which a network manager can view and control. Many businesses also deal with payment information flowing in and out of their networks, either for customer purchases or employee salaries, so their systems are required to be HIPAA and PCI-DSS-compliant — which isn’t always possible with consumer-grade firewall tech.

Businesses have other considerations as well, such as whether their routers or firewalls should be placed at the network edge. Edge routers are typically used to give access to remote workers so they can connect to the corporate network. In fact, the terms “edge routers” and “firewalls” are often used interchangeably to describe a network security device that protects the LAN from a point “between” networks.

Can a router and firewall be on the same device?

Certain software-defined networks and routers come equipped with software firewalls already installed. Some businesses prefer this because of the simplicity of having the two integrated. It just doesn’t make much sense to have multiple devices that need to be configured and managed separately, especially when each comes with its own potential setbacks.

Yet, for some businesses, the added labor is worth it to keep the devices separate. For instance, when all a router needs to do is route traffic to intended destinations, it will have a lot more resources to spare than if it were simultaneously doubling as the network’s firewall.

Likewise, if your network starts hiccupping, the single router-firewall device may not know how to share the limited network resources most efficiently. Depending on the unique network conditions, this can lead to dropped VoIP calls, laggy video conferences, or even security risks.

Finally, having a dedicated firewall allows you to be much more specific as to what you’d like that firewall to do — and how you’d like it to do it. Most businesses use both stateless and stateful firewalls and need a high degree of configurability over firewall rules.

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DHCP: When to Use it (And When Not to)

The Dynamic Host Configuration Protocol (DHCP) automatically assigns unique IP addresses to your devices, along with other necessary details like subnet masks and default gateway information. This process allows devices to communicate within the network and access the internet.

Automating this process, rather than manually configuring each device, saves a lot of time and reduces errors.

DHCP is a free and reliable way to configure devices on IP networks, but it isn’t without its drawbacks and security vulnerabilities. I’ll walk you through the advantages of it along with the tradeoffs, to help you understand when it’s apt to use.

Essential DHCP terms

To understand DHCP, there are a few other terms and technologies you will need to know:

  • IP address: An IP address is a unique identifier for each device on a network. DHCP can dynamically assign addresses from a pool of available numbers, letting devices communicate within the network and on the internet.
  • Subnet mask: This is a number that defines a range of IP addresses available within a network. It helps you divide networks into subnetworks for more efficient management and security.
  • DHCP server: This is a network server that assigns IP addresses, default gateways, and other network parameters to client devices. It relies on the DHCP to respond to broadcast queries by clients.
  • DHCP client: This is any device that requests and obtains an IP address and other parameters automatically from a DHCP server. Clients can include computers, smartphones, and other network-enabled devices.
  • Lease duration: Lease duration is the length of time an IP address is assigned to a device. After the lease expires, the device must request a new IP address or renew the existing one.
  • DNS server: A DNS server translates domain names into IP addresses so that network requests can be routed to the correct servers.
  • Default gateway: The default gateway is a device that serves as an access point or IP router to pass traffic from a local network to other networks or the internet.

How DHCP works

Let’s walk through the process step by step, breaking it down into five discrete stages that ensure seamless IP address allocation and network connectivity. Knowing the fundamentals of computer networking will be really helpful for understanding this process.

DHCP discover

The DHCP process begins when a client device connects to the network and needs to obtain network configuration parameters. It broadcasts a “DHCP discover” message to the network.

This message is a request for configuration information. Since the client device doesn’t yet have an IP address, this broadcast is sent to a special address that all DHCP servers listen to.

DHCP offer

After receiving the discovery message, a server on the network responds to the client, or device, with a “DHCP offer” message.

This message contains critical configuration data, like an available IP address from the server’s pool, subnet mask, and lease duration.

If there are multiple DHCP servers on the network, the client may receive several offers, each with different configuration options.

DHCP request

The client will evaluate all the offers it receives, then select one and respond to the network with a “DHCP request” message.

This message indicates the client’s acceptance of one of the offers and informs all DHCP servers on the network of the decision.

At this point, other servers that made offers will retract them and reserve those IP addresses for other devices.

DHCP acknowledgement

The server that made the selected offer responds to the client with a “DHCP acknowledgement” packet.

This finalizes the lease of the IP address to the client and may include additional configuration information, such as the DNS server address and default gateway.

The client configures its network interface with this information, establishing a connection to the network.

Lease duration and renewal

The process is essentially complete at this point, but the IP address lease is only valid for a specific duration, known as the lease time. This means that before the lease expires, the client must either renew its existing lease or request a new one.

If the client shuts down or leaves the network before the lease expires, it sends a “DHCP Release” message, relinquishing its IP address and making it available for other devices.

When it makes sense to use DHCP

Since DHCP can automate an otherwise tiresome manual process, we generally recommend it for most business and network environments.

Here’s the main reasons why I’ve found DHCP a good choice.

Dynamic network environments

In settings where devices frequently join and leave the network, such as businesses with multiple users or public Wi-Fi networks, DHCP is ideal. It dynamically allocates IP addresses, making it easier to manage a changing roster of devices. Doing this process manually would be much less efficient. If you want to support a Bring Your Own Device network, for example, I’d say DHCP is a must — though you will have to stay on top of BYOD security.

Reduced administrative workload

Since DHCP automates the process of assigning IP addresses, it frees up administrators to spend time on other things. This significantly reduces the workload for your network administrators and minimizes the chance of errors that can occur with manual IP assignments.

Scalability and flexibility

DHCP is highly scalable, so whether your network is small or expanding rapidly, it can adapt. It’ll continue to manage IP addresses efficiently as the number of connected devices on your network grows or shrinks.

When to avoid using DHCP

There are scenarios where assigning a static IP address makes sense. For example, servers, network printers, and other devices that need to maintain a consistent network address for easy accessibility are better suited to static IP addresses.

DHCP can also present security risks or become a single point of failure in a network if it’s not properly secured and monitored. Since IP addresses are assigned dynamically, it can be challenging to track which device had a particular IP address at any given time.

If your server goes down, new devices may be unable to connect to the network, and existing devices may encounter issues upon lease renewal.

What you need to set up DHCP

If you’re clear on the pros and cons and have decided to go with DHCP, there are a few steps you’ll need to take to get everything set up.

  1. DHCP server: The central element of any DHCP setup is the server. This can be a dedicated server, a network router with DHCP capabilities, or a virtual server running on a networked computer. Whatever you choose, the server needs to be reliably connected to your network and configured to manage IP address allocation.
  2. Configurable IP address pool: The server needs a range of IP addresses, known as a pool, from which to assign them to client devices. This pool should be carefully planned to ensure there are enough addresses to accommodate all devices on your network.
  3. Network information: The server also distributes other network information to clients besides IP addresses. This includes the subnet mask, default gateway, and DNS server addresses.
  4. DHCP configuration parameters: You’ll need to set parameters on the DHCP server, such as the lease duration and any specific configuration options required by your network.
  5. Network security considerations: If you’re implementing DHCP in a business environment, your network needs to be secure. Setting up firewalls, securing the DHCP server against unauthorized access, and regularly monitoring network activity are crucial. You can also consider investing in data loss prevention software.
  6. Backup and redundancy: You should always have a backup server or a failover system, which I’ll talk more about below. This can help ensure continuous network operation even if your primary DHCP server runs into issues.

How to get the most out of DHCP

Once your DHCP is up and running, here’s what I recommend you do to maximize its effectiveness.

Regularly update and audit DHCP settings

To maintain security and performance in your network, you’ll need to regularly update and audit your settings. Keep an eye on your IP address pools. As your network evolves, the range of IP addresses allocated by DHCP should be adjusted. This ensures there are always enough addresses to meet demand without over-allocating resources.

Choosing the right lease durations is also key. The appropriate length for leases can vary depending on how your network is used. For example, in a dynamic environment where devices frequently come and go, shorter lease durations might be more effective. In more stable networks, longer leases can reduce the administrative overhead of continually reassigning IP addresses.

Implement DHCP failover for high availability

By setting up a DHCP failover system, you can prevent a single point of failure in your network. The process involves configuring a secondary DHCP server that can take over the responsibilities of the primary server in case it fails or goes offline.

In other words, your server needs to be accounted for when you create a business continuity plan. It’s a critical part of your infrastructure.

The key is to configure both servers so that they have synchronized lease information. Aside from maintaining uninterrupted network service, this also ensures that IP address allocation continues without glitches. This step is particularly important if you’re operating in an environment where network reliability is critical, like large enterprises or service provider networks.

It’s also a good idea to test your failover. Doing so will ensure that it functions as expected when it matters most, like during a server outage.

Segregate networks with DHCP scope

A DHCP scope is a defined range of IP addresses that the server can assign to clients. By defining scopes, you can control how IP addresses are distributed across different segments of your network.

Creating different scopes for various departments, floors, or types of devices helps in efficient network organization and management. This level of segregation can improve network performance, enhance security, and simplify troubleshooting.

What’s more, you can also implement specific security policies or restrictions for each subnet. This can help prevent the spread of network threats and manage controls — just make sure your scopes are configured in a way that prevents IP address conflicts within your address pool.

Manage DHCP scopes

Once scopes are configured, they need to be regularly monitored. If a scope reaches its capacity, it’s a sign that you either need to expand the range of IP addresses in that scope or reevaluate the network’s IP address usage. High utilization rates can lead to IP address exhaustion, where new devices can’t join your network.

Certain devices are better suited for static IP addresses rather than DHCP, it’s true. With scopes, you can set up exclusion ranges for your servers, printers, and other network equipment. Exclusion ranges prevent the server from assigning these addresses dynamically, reducing the risk of IP conflicts.

Monitor and analyze DHCP traffic

Checking over your DHCP traffic will not only help boost your network performance, but also help keep security risks to a minimum.

Implementing tools with real-time monitoring will help your network administrators track where your IP addresses are going. Real-time monitoring can also help flag sudden surges in IP requests, usual network issues, or malicious activities.

You can also set up security alerts for abnormal activities, like multiple failed IP address assignments or requests from unauthorized devices. Detecting these things early can help prevent network intrusions, spoofing attacks, and other network security threats.