How do I login to my KT GiGA WiFi Home router?

Connect to Wi-Fi, open a browser, and go to http://172.30.1.254. The default ID is 'ktuser'. The password is usually 'homehub' or 'megaap' followed by '!' (e.g., homehub!), or check the sticker on the device.

What does the red 'OPT' light mean on my KT modem?

A red 'OPT' light indicates a loss of optical signal. This means the fiber cable coming into your home is damaged, unplugged, or there is a cut in the line outside. You must call 100 (KT Customer Center) for a technician.

Why is my ping high when playing games on overseas servers?

KT generally has the best overseas routing in Korea, but physics limits latency to US/EU servers (150ms+ is normal). If you experience spikes, try using a wired Ethernet connection instead of GiGA WiFi to eliminate local wireless interference.

KT Speed Test

This tool validates Internet speeds for KT (Korea Telecom) subscribers. Whether you use the popular GiGA Internet (1Gbps/500Mbps) or the ultra-fast 10 GiGA Internet, use this test to verify you are getting what you pay for.

KT is South Korea's largest ISP, known for its extensive fiber-optic network (FTTH) and "GiGA WiFi Home" routers. However, daily data caps (QoS) and hardware configuration can affect your speed.

Understanding KT Speed Results

Your test results depend heavily on your plan and daily usage:

Download Speed: For the standard "GiGA Internet 1G" plan, expect 800-950 Mbps on a wired connection. Speeds below 100 Mbps often indicate a bad cable (Cat5) or that you have hit your daily QoS limit.

Upload Speed: KT provides symmetric speeds (FTTH). Your upload should match your download speed (e.g., ~900 Mbps upload for a 1Gbps plan).

Ping (Latency): KT offers excellent latency. Prefer wired connections for domestic games (Sudden Attack, LoL, PUBG) where ping should be under 5ms.

Daily QoS Limit (Speed Throttling)

Many users are unaware that KT applies a Daily Data Cap (QoS) on residential GiGA plans.

The Rule: If you transfer more than 150GB generally (varies by contract) in a single day, your speed is instantly throttled to 100 Mbps for the rest of that day.

The Fix: There is no manual fix. The speed resets automatically at midnight (00:00). This is not a technical fault; it is a policy restriction.

KT Router Login (172.30.1.254)

To change your Wi-Fi password or set up port forwarding for gaming, access the "GiGA WiFi Home" admin page.

KT Admin Details	Information
Gateway IP	172.30.1.254
Default ID	ktuser
Default Password	homehub or megaap (Note: Older models use 'homehub', newer ones often use 'homehub!' or check the bottom sticker)

Login Instructions

Ensure you are connected to the KT router (LAN or Wi-Fi).
Enter http://172.30.1.254 in Chrome/Edge.
Enter the ID (ktuser) and Password.
Type the security CAPTCHA code shown on screen.
Click Login.

Troubleshooting Gateway Lights

Power (Green): Normal operation.

OPT (Red): Optical signal lost. The fiber cable is broken or disconnected. Call 100 instantly.

Internet (Green): Connected to KT network.

USB (Off): Normal if no USB storage is attached.

When to Contact KT Support (100)

Dial 100 (from a mobile or landline) if:

The OPT light is flashing red/orange.

You have not downloaded much data but speeds are stuck at 100 Mbps (possible provisioning error).

You need to replace an old router with a new Wi-Fi 6 (ax) model.

KT Speed Test FAQs

Why did my KT internet speed suddenly drop to 100 Mbps? You likely hit the daily QoS limit (often 100GB or 150GB). KT throttles lines to 100 Mbps after this limit is reached to prevent network abuse. It resets at midnight.

My ping is high in games. How do I fix it? If you are using GiGA WiFi, switch to a LAN cable (Cat6). Wireless interference in Korean apartments is extremely high. Also, check if you are downloading large files, which can saturate the heavy NAT session table.

How do I change my GiGA WiFi password? Log in to 172.30.1.254, go to 'Easy Setup' or 'Wireless Configuration', change the 'Pre-shared Key', and click Apply.

What is the difference between GiGA Internet and GiGA WiFi? 'GiGA Internet' is the line service coming into your wall. 'GiGA WiFi' is the router equipment that broadcasts that signal wirelessly. You need both for fast wireless speeds.