Wi-Fi Connected But No Internet After New AP Installation

Quick answer

If Wi-Fi says connected but there is no internet after installing a new access point, the wireless connection may be fine but the access point may not have a working path back to the router, DHCP server, DNS, or correct VLAN.

Beginner-friendly version: connecting to Wi-Fi is only step one. The AP still needs to be connected properly to the rest of the network. Cantonese-friendly: “連到 Wi-Fi 唔代表出到街，AP 後面條路都要通.”

Symptoms

You may see:

• Devices connect to the SSID but websites do not load.
• Phones show “No Internet” or “Connected without internet.”
• Devices get a 169.254 IP address.
• Devices get an IP address but cannot ping the gateway.
• Wired devices still work, but Wi-Fi devices do not.
• Only the new SSID or new AP location has the issue.

What it usually means

The client device can talk to the access point, but something behind the access point is wrong or incomplete.

The issue could be uplink, switch port configuration, VLAN tagging, DHCP, DNS, gateway, firewall rules, or an SSID setting. The Wi-Fi signal strength can look excellent while the network behind it is misconfigured.

Common causes

Common causes include:

• The AP uplink cable is unplugged, damaged, or connected to the wrong port.
• The switch port is not configured for the VLAN used by the SSID.
• The AP expects tagged VLANs, but the switch port is access-only.
• DHCP is not available on the Wi-Fi VLAN.
• The SSID is mapped to the wrong network.
• DNS is missing or unreachable.
• A captive portal, firewall rule, or guest network setting blocks traffic.
• The AP is powered by PoE but has no data path due to cabling or port setup.

Step-by-step troubleshooting

1. Confirm the scope of the issue.

Ask whether all Wi-Fi users are affected, only one device, only one SSID, or only one access point. Scope tells you where to look.

2. Check the client IP address.

On a connected device, check IP address, subnet mask, default gateway, and DNS. A 169.254 address points toward DHCP failure. A normal IP with no internet points toward gateway, DNS, routing, or firewall.

3. Test the AP uplink.

If possible, unplug the AP and connect a laptop to the same Ethernet cable. If the laptop cannot get a valid IP or reach the internet, the issue is upstream from the AP.

4. Check switch port mode.

Confirm whether the switch port should be an access port or trunk port. If the AP broadcasts multiple SSIDs with VLANs, the port usually needs the correct tagged VLANs allowed.

5. Review SSID-to-VLAN mapping.

Make sure the SSID is mapped to the intended VLAN. Guest Wi-Fi, staff Wi-Fi, and management networks may all behave differently.

6. Confirm DHCP on that network.

Check that the VLAN has a DHCP scope and, if needed, a DHCP relay or helper address. If DHCP works on wired but not Wi-Fi, compare the VLANs.

7. Test DNS and gateway.

Try pinging the default gateway. If that works, test a public IP and then a domain name. If IP works but names fail, DNS is likely the problem.

8. Review AP and firewall settings.

Check client isolation, guest restrictions, captive portal settings, blocked LAN access, or firewall rules that may be intentional but too restrictive.

Beginner note

Wi-Fi has layers. First the device connects to the SSID. Then it needs a valid IP address. Then it needs a gateway and DNS. Then firewall and routing must allow traffic. Troubleshooting is easier when you test one layer at a time.

Real-world note

After a new AP installation, many problems come from switch port and VLAN mismatch. The AP may be configured correctly and the switch may be configured correctly for a different design, but the two sides do not agree.

Common mistakes

• Judging the issue only by signal strength.
• Rebooting the AP repeatedly without checking IP addressing.
• Forgetting that guest Wi-Fi may intentionally block internal network access.
• Mapping the SSID to the wrong VLAN.
• Leaving the AP management VLAN correct while the user Wi-Fi VLAN is broken.
• Testing from a phone only and not checking the actual IP details.

Help desk interview angle

For an interview answer, keep it structured:

“I would first confirm whether the issue affects one device or all clients on that AP or SSID. Then I would check the client IP, gateway, and DNS. If clients have APIPA, I would check DHCP and VLAN path. If they have valid IPs, I would test gateway, DNS, routing, and firewall rules. Since it happened after a new AP install, I would pay close attention to uplink and switch port VLAN configuration.”

FAQ

Does connected Wi-Fi mean the AP is working?

Only partly. It means the client can associate with the AP. It does not prove DHCP, DNS, routing, or internet access works.

Why do devices get 169.254 after connecting to Wi-Fi?

They connected to the AP but did not receive DHCP. Check VLAN, DHCP scope, DHCP relay, and the AP uplink path.

Should I reset the access point?

Not as the first step. Check IP details, uplink, VLAN, and DHCP first. Resetting can remove useful configuration and make the issue harder to compare.

Could DNS be the only problem?

Yes. If the device has a valid IP and can ping an outside IP address but cannot open domain names, DNS is a strong suspect.