If you have no internet after installing a new router or modem, the timing is one of the strongest diagnostic clues. If the internet worked immediately before the equipment changed, start with the new network setup rather than assuming the NBN connection or every device in the house suddenly developed a separate fault.
A new modem or router can create a perfectly normal Wi-Fi network even when it has not established a working connection to the internet. Your phone or computer may therefore show strong Wi-Fi and appear connected while websites, email and apps still fail.
The useful path to think about is:
NBN or ISP connection -> modem/router -> Wi-Fi -> device
After a router replacement, the most important question is where that path stops working.
First, check whether every device has lost internet
Before changing settings, test another phone, computer or tablet on the new Wi-Fi network.
- π No devices have internet: concentrate on the new modem/router, its WAN connection, NBN cabling and ISP configuration.
- π» Only one device is affected: the new router may be working and the problem may instead involve that device’s saved network, IP, DNS or adapter settings.
- π± Some devices work and others do not: look for old Wi-Fi profiles, static network settings, compatibility issues or devices still connecting through older network equipment.
If nothing in the house can get online, the broader guide to Wi-Fi connected but no internet on all devices explains why troubleshooting should move outward toward the router, NBN connection and ISP rather than focusing on one computer.
Check the connection into the new modem or router
One of the simplest problems after a replacement is also one of the easiest to overlook: the internet connection may be plugged into the wrong port, using the wrong cable path, or not connected in the way the new router expects.
On NBN services that use a separate connection box, an Ethernet cable will normally run from the active NBN connection to the router’s WAN or Internet port. Connecting that cable to one of the router’s ordinary LAN ports can leave the Wi-Fi working while the router itself has no upstream internet connection.
Other NBN connection types can use a DSL connection directly into the modem-router instead, so copying the cable arrangement from a different type of router is not always enough.
Check for:
- π The incoming NBN or internet cable connected to the correct port on the new equipment.
- 𧡠Ethernet cables that are fully seated at both ends and have not been moved to the wrong socket during the changeover.
- π¦ Any separate NBN connection box still powered and showing its normal service indicators.
- π Old routers, mesh units, switches or extenders that may still be connected in a way that no longer matches the new network layout.
Wi-Fi working does not mean the router has internet
This distinction causes a lot of confusion after a modem replacement.
The new router can broadcast its Wi-Fi name, accept the Wi-Fi password and give your phone or laptop a local network connection without having any usable internet connection of its own.
In other words:
Device -> Wi-Fi -> Router may be working while Router -> Internet is not.
That is why repeatedly reconnecting phones and laptops rarely helps when every device has the same problem.
The new router may still need ISP configuration
Replacing a router is not always simply a matter of plugging it in.
Depending on the internet provider and connection, the router may need particular WAN settings before the service will work. Some connections obtain their settings automatically, while others may require ISP login details, a particular connection method or additional provider-specific configuration.
Possible problems include:
- βοΈ The WAN or Internet connection has not been configured.
- π Required ISP credentials were not transferred from the old modem.
- π·οΈ Provider-specific connection settings are missing or incorrect.
- π‘ A provider-supplied replacement modem has not completed activation or provisioning.
- π A privately purchased router is using default WAN settings that do not match the service.
This is also why a router that worked at another property or with another internet provider cannot always be moved across unchanged.
Make sure the new equipment is actually operating as the router
Many modern routers and mesh systems can operate in several modes. The same hardware might function as the main router, an access point, a bridge or part of a mesh network.
If the replacement equipment is in the wrong mode, devices may successfully join Wi-Fi without being given a usable route to the internet.
This is particularly worth checking when:
- πΆ A mesh system has been added at the same time as the new modem.
- π The old router is still connected somewhere in the network.
- 𧩠The new equipment was previously configured as an access point or secondary router.
- π§ Settings were copied from an old configuration without checking how the new hardware is connected.
The Wi-Fi name and password may have changed too
A router replacement usually creates a new local network as well as replacing the device that connects to the internet.
If the new router has a different Wi-Fi name or password, every wireless device needs to join the correct network. Computers, televisions, printers, tablets and smart-home equipment may otherwise continue looking for the old Wi-Fi.
It is also possible for an old extender or mesh unit to continue broadcasting the previous network name. A phone or laptop can then appear connected while actually using network equipment that is no longer correctly attached to the internet.
If you deliberately gave the new router the same Wi-Fi name and password as the old one, many devices will reconnect automatically, but not every device handles the change cleanly. Some may retain old network information and need to be reconnected individually.
Old IP, gateway or DNS settings can affect individual devices
A replacement router may use a different local network range from the old one.
Most home devices obtain their network settings automatically using DHCP and adjust without any intervention. A computer or other device that was previously configured with a manual IP address, gateway or DNS server may not.
That becomes especially relevant when most devices work on the new router but one particular computer, printer or other network device does not.
A modem change can therefore expose an old manual configuration that appeared perfectly normal on the previous network.
Check the NBN and ISP side before changing more settings
The timing may strongly suggest the new router, but the upstream service still needs to be checked.
Look at the NBN equipment and the router’s internet or WAN status. If the NBN connection itself is down, the service has not been activated, or the ISP has an account or provisioning problem, no amount of Wi-Fi troubleshooting will restore the upstream connection.
The distinction matters because the eventual fix may belong to different parties:
- π οΈ Local problem: cabling, router setup, Wi-Fi configuration, DHCP, DNS, mesh configuration or device networking can often be corrected onsite.
- βοΈ Provider problem: an ISP account, provisioning issue, NBN fault or upstream outage may ultimately need the internet provider to resolve it.
A factory reset is not a stronger restart
If the new router is already partly configured, avoid factory resetting it simply because restarting did not help.
A factory reset removes configuration. It can erase working ISP settings, Wi-Fi details and other network changes and leave you with more variables than you started with.
If you have already restarted the equipment and the connection still fails, the next step should normally be diagnosis rather than another variation of rebooting. The guide on what to check after you have restarted the router but still have no internet covers that escalation in more detail.
What if the internet works but another device stopped working?
Restoring internet access does not necessarily mean every device on the old network will immediately return to normal.
Printers, scanners, smart-home devices and other network equipment may still remember the old Wi-Fi name, password or local network address. That is a separate consequence of changing the router rather than evidence that the new internet connection has failed again.
When the problem started with the new router, follow the change
The useful question is not simply, “Why is my Wi-Fi not working?” It is, “What changed when this router was installed?”
If the connection worked beforehand, there is usually a finite path to check: the incoming NBN connection, the cable into the router, WAN configuration, ISP provisioning, router mode, the new local network and finally the devices connected to it.
PcRiot provides onsite Wi-Fi and internet troubleshooting in Perth for homes and small businesses when it is unclear whether a connection problem belongs to the computer, modem/router, local network or internet provider.
After a modem or router replacement, PcRiot can check:
- π The NBN-to-router connection and local network cabling.
- π WAN connectivity and the router’s internet configuration.
- π‘ The new Wi-Fi network, mesh equipment and connected devices.
- π§ DHCP, gateway and DNS behaviour across the network.
- π§ͺ Whether the fault is inside the home network or needs to be referred back to the ISP.