A wireless communications device for IP address negotiations is provided and comprises a wireless module, a connection device, and a processing unit. The wireless module provides wireless communications from and to a service network. The connection device is coupled to the terminal device. The processing unit is coupled to the connection device and the wireless module, receiving an IP address request message from the terminal device via the connection device, and requests an IP address and a DNS address from the service network via the wireless module in response to an IP address request message from the terminal device. Also, the processing unit determines whether allocated IP address and DNS address have been received from the service network, and sends a rejection message to the terminal device to trigger the terminal device to resend the IP address request message in response to determining that the allocated IP address and DNS address have not been received from the service network.