Most DIR routers all use the very same "master access" password. This password allows "us" to configure the router settings such access Internal access a WiFi security.
The DIR-825 has "limited" hardening possibilties. You can:
- Change access password
- Setup and maintenance the Wireless (WiFi) access security. Use WPA2-AES as the WiFi Passphrase "settings" in the Wireless Security
- Enter a list of network adapters (PCs and other devices) MAC IDs that are allowed to access your router (*)
- Hide the wireless network name (SSID) (*)
(*) -- These settings do not help with security access but can "help?"
If you want an hardened router, you will need to look at the more advanced "true" firewall devices.