Every router has an IP address that allows you to log in to the admin settings of the router. Users can configure the router and network settings using the default gateway. 192.168.15.1 is one such IP address which can be used to login to routers like D-link VWr-VR, Clear WIXFBR-117 and Linksys RT31P2, Linksys WRP400 / WRT54GP2, Motorola and Sweex.