Depois de analisar sua resposta aceita, cheguei a esta página de manual que pode ajudar você a entender o que está acontecendo aqui.
Do manual do usuário para Kerio WinRoute Firewall 6
Logout
Once finished with activities where authentication is required, it is recommended to log out of the firewall by using the Logout button. It is important to log out especially when multiple users work at the same host. If a user doesn’t log out of the firewall, their identity might be misused easily.User can be logged on the firewall even if they have not used the web interface — e.g. if the firewall required user authentication during access to a website. To make user avoid opening the web interface when finishing their work and clicking on Logout, WinRoute includes a direct link for user logout: http://server:4080/logout or https://server:4081/logout
This URL performs immediate logout of the user without the need of opening of the web interface’s welcome page.
Hint: URL for user logout from the firewall can be added to the web browser’s toolbar as a link.
User can use this “button” for quick logout.
Então, talvez você possa substituir seu wget
hack por esse método formal.