To set Buffalo router as repeater, just follow these guidelines that are described here -
First of all, find the IP address of your Buffalo router. For this, open Command Prompt and type “ipconfig” and then press Enter key.
After getting your router’s IP address, you have to reset Buffalo router. Locate the Reset button on the backside of Buffalo router and gently press it for some moments until “Diag” light illuminates.
After resetting, wait for a couple of minutes and connect Buffalo router to PC by using an ethernet cable. Make sure you have to connect to LAN port instead of WAN port. Well, you can plug an ethernet cable into any of the 4 LAN ports.
Again, wait for a couple of minutes until your system’s LAN icon shows an exclamation mark. Also, confirm that you have switched to WiFi. After this, open Internet Explorer, type “192.168.11.1” to access the Buffalo router login page. Go ahead and type Buffalo router’s username and password in the required fields.
Now, move directly to Basic Settings. At this moment, confirm that your router is turned on. Navigate to WAN connection type and set it as DHCP. Also, provide a name if you want. Click Save.
Move to router’s IP address field box and leave it as it is unless main internet router’s IP is in that range. Confirm that router’s main IP is not conflicting with any another. Also, confirm the subnet mask is different.
Subnet Mask – 255.255.255.0
Gateway - 192.168.100.1
DNS – 192.168.100.1
After entering these values, click on Save button.
Move to bottom, turn on DHCP. Its IP will be like 192.168.11.(). In the blank space, you can enter any number except 1. Although DHCP is set as “50”. In other words, the IP address of your device will range from 192.168.11.100 to 192.168.11.149. Click on Save.
In next step, tap on Wireless > Physical Connection. Choose the connection mode as WDS. After this set the SSID same just like as main internet router.
If you didn’t find virtual network settings, just tap on Add. Choose WDS AP below and type the same SSID. Save the settings.
Move to wireless security and enter a complex password. Go ahead and set the security settings to “TKIP+AES”. At last, click on “Apply Settings”.
Now, wait for a couple of seconds, until your Buffalo router reboots.
If you face any trouble at any step then please revert back, I will definitely help you by giving a perfect solution.