The following formula is very useful to provide login/logout links for those servers that have session authentication enabled. The login link show only when the user has not authenticated. The logout link only shows when they are authenticated. The logout link also redirects after the logout, back to the current database, but this can easily be changed by modifying the portion of the formula directly after the "Redirectto" section.
Place the following formula in Computed Text
REM "Script to create login/logout link"; MyDB :=@ReplaceSubstring(@Subset(@DbName;-1);"";"/"); @SetTargetFrame("_top"); "[<a href=""+@If(@Name([CN];@UserName) = "Anonymous"; "/"+MyDB+"?OpenDatabase&Login" target=_top>Login</a>]"; "/"+MyDB+"?Logoutℜdirectto="+MyDB+"" target=_top>Logout</a>]")