How To • IP and DHCP Issues • Router Configuration

How to choose IP reservations for key devices

This guide will show you how to assign a permanent IP address to important devices like your printer, NAS, or smart home hub using your router's DHCP reservation feature.

You'll learn how to find your device's MAC address, log into your router, and configure a reservation to prevent address changes, ensuring reliable connections for critical services.

Note: Steps may vary by device and router model. This guide focuses on safe, general methods.

Quick Answer

Log into your router's admin page (usually via 192.168.1.1 or 192.168.0.1).
Find the "DHCP Server" or "LAN Setup" section, then look for "Address Reservation" or "Static DHCP".
Find the MAC address of your key device (check its network settings or your router's client list).
Choose an IP address outside your router's main DHCP pool (e.g., if pool is 192.168.1.100-200, use 192.168.1.50).
Enter the MAC address and chosen IP, then save the reservation.
Restart the key device to receive its new permanent IP.

If this doesn't work, follow the diagnostic flow below to check for conflicts or incorrect settings.

What you need

Before you start

Admin username and password for your router.
The device you want to assign a permanent IP to must be connected to your network.
A computer or phone on the same network to access the router.
Basic understanding of your network's IP range (e.g., 192.168.1.x).
5-10 minutes of focused time.

Good to know

DHCP reservation is safer than setting a static IP on the device itself.
The MAC address is a unique hardware ID, not the device's name.
Choose an IP address outside the DHCP "pool" to avoid conflicts.
Reservations are stored on the router; resetting the router may erase them.
Useful for servers, printers, smart home hubs, and gaming consoles.

Diagnose the issue in 2 minutes

Is your device's IP address changing unexpectedly?
- Yes: Proceed with setting up a DHCP reservation.
- No: A reservation may not be necessary unless you need fixed IPs for port forwarding.
Can you access your router's admin page?
- No: Check your connection and find your router's default gateway IP.
- Yes: Move to the step-by-step guide.
Quick checks:
- Find your IP: Open command prompt/terminal and type ipconfig or ifconfig. The "Default Gateway" is your router's IP.
- Find device MAC: Check the device's network settings or the router's connected client list.
- Check for IP conflict: If a device gets "IP conflict" error, you likely have a duplicate static IP.

Step-by-step guide

Step 1 — Identify your key device and network

Determine which device needs a permanent IP and note your current network details.

Connect the device (printer, NAS, etc.) to your network.
On a computer, find your router's IP (default gateway) and your network's subnet (usually 192.168.1.x or 192.168.0.x).

Windows: Open Command Prompt, type ipconfig. Look for "IPv4 Address" and "Default Gateway".

macOS/Linux: Open Terminal, type ifconfig or ip addr show. Find the "inet" address for your active connection.

What you should see: Your computer's current IP (e.g., 192.168.1.25) and the router IP (e.g., 192.168.1.1).

Step 2 — Find the device's MAC address

The MAC address is required for the reservation. It's often labeled as "Physical Address" or "Hardware Address".

Method A (Router): Log into your router and find the "Attached Devices", "DHCP Client List", or "Network Map" section. Find your device and copy its MAC address.
Method B (Device): Check the network settings on the device itself. Some printers display it on a config page; for computers, use ipconfig/ifconfig and look for "Physical Address".

What you should see: A 12-character code like AA:BB:CC:11:22:33 or AA-BB-CC-11-22-33.

Step 3 — Access your router's DHCP settings

Log into your router's web interface to find where reservations are made.

Open a web browser and enter your router's IP address (from Step 1).
Enter the admin username and password.
Navigate to "LAN Settings", "DHCP Server", "Network", or "Advanced Settings".
Look for "Address Reservation", "Static DHCP", "DHCP Reservation", or "IP & MAC Binding".

What you should see: A list of current DHCP leases and a form to add a new reservation.

Step 4 — Choose a suitable IP address

Pick an IP that won't be handed out automatically by the router to other devices.

In your router's DHCP settings, find the "DHCP Pool" or "Range" (e.g., 192.168.1.100 to 192.168.1.199).
Choose an IP address outside this range but within the same subnet. For example, use 192.168.1.50.
Avoid using the router's own IP (usually .1) or common low numbers like .2 that might be used by other static devices.

What you should see: A clear understanding of which IPs are dynamic (auto-assigned) and which are safe for permanent use.

Step 5 — Create the reservation

Enter the device's MAC address and your chosen IP address.

Click "Add", "Create", or a similar button in the reservation section.
Paste or type the device's MAC address. Ensure the format matches your router's preference.
Enter the chosen IP address you selected in Step 4.
Optionally, give the entry a descriptive name (e.g., "Office Printer").
Save the changes. The router may ask to reboot; this is often not required immediately.

What you should see: The new reservation appearing in the list of reserved addresses.

Step 6 — Verify and test the configuration

Ensure the device now receives the correct IP address.

Restart the key device (power cycle it) to force it to request a new IP from the router.
Once it's back online, check its assigned IP address via its settings menu or your router's client list.
Test connectivity to the device using its new permanent IP (e.g., ping it or access its web interface).

What you should see: The device connected with the exact IP address you reserved. Other devices should not receive this IP.

Common fixes by symptom

IP address conflict error

Likely causes:

Manually set a static IP on the device that's also in the DHCP pool.
Another device on the network has a manual static IP matching your reservation.

Safe fixes:

On the key device, set its IP configuration back to "Obtain automatically" (DHCP).
Change your reserved IP to a different address further from the DHCP range.

When to stop and escalate: If conflicts persist after adjusting ranges, check for unauthorized devices on the network.

Device gets wrong IP after reservation

Likely causes:

Entered the MAC address incorrectly.
Did not save/apply router settings properly.
Device cached an old DHCP lease.

Safe fixes:

Double-check the MAC address in the router's client list versus your entry.
Reboot the router to clear all DHCP leases, then reboot the device.
On the device, run ipconfig /release then ipconfig /renew (Windows).

When to stop and escalate: If the router firmware seems buggy and doesn't honor reservations, consider a factory reset or firmware update.

Cannot access router admin page

Likely causes:

Using the wrong IP address for the router.
Being on a different network (e.g., guest Wi-Fi).
Browser cache or firewall blocking access.

Safe fixes:

Use the default gateway IP found via ipconfig/ifconfig.
Ensure your device is connected to the main network, not the guest network.
Try a different browser or incognito mode.

When to stop and escalate: If you've forgotten the admin password, a router factory reset may be needed (this erases all settings).

Reservation lost after router reboot

Likely causes:

Router firmware bug.
Settings not permanently saved before reboot.

Safe fixes:

Re-enter the reservation and look for a "Save Configuration" or "Backup Settings" option.
Check for a firmware update for your router model.

When to stop and escalate: If the router consistently fails to save settings, it may be a hardware fault.

Quick reference

A. What the metric means

Metric	What it tells you	Good Range
Latency (Ping)	Time for a data packet to reach a server and return. Affects real-time apps.	< 50 ms (local), < 100 ms (online)
Jitter	Variation in latency. Causes choppy voice/video calls.	< 30 ms
Packet Loss	Percentage of data packets that never arrive.	0% (anything > 1% is problematic)
Throughput	Actual speed of data transfer (vs. advertised speed).	Close to your subscribed plan speed.
Signal Strength	Power of the Wi-Fi signal received by your device.	-50 dBm (excellent) to -70 dBm (fair).

B. Safe baseline settings

Setting	Recommended Choice	Why
Wi-Fi Security	WPA2/WPA3 Personal (AES)	Strong encryption, widely compatible, secure.
DNS Servers	Router default or trusted public DNS (e.g., 1.1.1.1)	Balances speed, privacy, and reliability.
Router Admin Password	Unique, strong password, not the default.	Prevents unauthorized access to network control.
Guest Network	Enabled with separate password.	Isolates guest devices from your main LAN for security.
Firmware Updates	Enable auto-update if available, or check quarterly.	Patches security holes and improves stability.

Mind map summary

CHOOSE IP RESERVATIONS
|
├── Why? → Stable IP for servers, printers, port forwarding.
|
├── Prerequisite → Router admin access, device MAC address.
|
├── Process
│   ├── 1. Find device MAC (router client list or device settings).
│   ├── 2. Log into router (via default gateway IP).
│   ├── 3. Locate "DHCP Reservation" settings.
│   ├── 4. Pick IP outside DHCP pool (e.g., .50 if pool is .100-.200).
│   ├── 5. Bind MAC to chosen IP, save.
│   └── 6. Restart device, verify new IP.
|
├── Pitfalls
│   ├── IP Conflict → Caused by overlapping static IPs.
│   ├── Wrong IP → Check MAC address accuracy.
│   └── Lost setting → Router may need firmware update.
|
└── Alternatives
    ├── Static IP on device → Riskier, harder to manage.
    └── Do nothing → Accept dynamic IP changes (fine for most clients).

Troubleshooting checklist

Device

MAC address copied correctly?
IP configuration set to DHCP/Auto?
Device restarted after reservation?
Can you ping the router from the device?

Router

Reservation saved and appears in the list?
Chosen IP is outside the DHCP pool range?
Router firmware up to date?
No other static IPs conflict with reservation?

Network

All devices on the same subnet?
Guest network isolation is off for this device?
Any firewall rules blocking the device?
Test with another device to rule out ISP issues.

When to escalate

Contacting ISP: Only if the problem is with your internet connection itself (all devices have no internet), not internal IP addressing.
Replacing router: Consider if the router consistently fails to save settings, has very outdated firmware with security risks, or lacks essential features like DHCP reservation.
Asking IT support: If you are managing a business network with complex VLANs, multiple subnets, or enterprise devices that require professional configuration.

What to collect before escalating:

Screenshots of your router's DHCP reservation and pool settings.
The MAC and desired IP of the problematic device.
Any error messages from the device or router logs.
A simple network diagram showing which device is having the issue.

FAQ

What is the difference between a static IP and a DHCP reservation?

A static IP is configured directly on the device itself, telling it to always use a specific address. A DHCP reservation is configured on your router; the router always assigns the same specific IP to that device when it requests one. The latter is often easier to manage centrally.

Why choose an IP outside the DHCP pool?

To prevent the router from accidentally giving your reserved IP to another device. The DHCP server automatically hands out addresses from its defined pool. If your reservation is inside that pool, some routers might still assign that address to a different device, causing a conflict.

Will a reservation work if the device is set to a static IP?

No. For the reservation to work, the device must be configured to obtain its IP address automatically (via DHCP). If it's set to use a static IP, it will ignore the router's offer of the reserved address.

Do I need to reserve an IP for my phone or laptop?

Usually not. IP reservations are most useful for devices that provide network services (like a printer or file server) that other devices need to find consistently. Client devices like phones and laptops work fine with dynamic IPs.

How many IP reservations can I make?

This limit depends on your router's firmware. Most consumer routers support at least 20-30 reservations, which is more than enough for a typical home. For dozens of devices, check your router's specifications.

What happens to my reservation if I reset my router?

A factory reset erases all custom settings, including DHCP reservations. You will need to set them up again. Some routers allow you to backup and restore a configuration file, which can save this information.

Can I use DHCP reservation with a guest network?

Typically, no. Guest networks are usually on a separate, isolated subnet, and devices on them get IPs from a different DHCP pool. Reservations are generally managed on the main LAN. It's also uncommon to need a fixed IP for a guest device.

My device has two MAC addresses. Which one do I use?

Some devices have separate MAC addresses for wired (Ethernet) and wireless (Wi-Fi) interfaces. Use the MAC address corresponding to the connection method the device is using. If you switch connection types, you may need a separate reservation for the other MAC address.

Sources and references

IEEE 802 standards overview for network addressing concepts
Router vendor administration guides (general DHCP server functionality)
Microsoft Windows documentation for TCP/IP networking and ipconfig utility
Apple support documentation for macOS network configuration
Linux manual pages for ifconfig, ip, and dhclient commands
Networking fundamentals textbooks covering the DHCP protocol (RFC 2131)
General cybersecurity best practices for home network management
Online knowledge bases for common consumer router firmware (e.g., ASUSWRT, DD-WRT, OpenWrt concepts)

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