I have total two routers. One is wireless (Linksys wrt54) and another is ADSL router. You do not have to use GUI program to modify settings. You can modify settings using special software provided by router manufacture or use standard web based configuration option.
- Open your web browser (Firefox or Internet Explorer)
- Type routers IP address (the default for most router is 192.168.1.1)
- When prompted type username and password (again default for most router is admin/password or admin/admin)
- Now you can modify the settings
- Just click on appropriate links or tabs to change the settings
- Do not forget to save settings