The basic settings on the Speedtouch 716 are fine but there are a couple of changes you might want to make.
First the basic setting for the modem is to allow all traffic in and out. This is a poor choice as it allows in all incoming attacks and malware. It is far better to select the standard security profile that stops all incoming traffic and only allows traffic out. Even better is to take the secure profile, that lets nothing in or out, and modify a copy of it to allow our port 80 and 443 for HTTP and HTTPS respectively. You can of course open other ports as and when you need them. The default of allowing nothing and adding only what you need is a good approach for security.
Secondly the universal plug and play or UPnP feature is enabled. This might seem like a nice idea: UPnP allows applications to automatically configure ports on your firewall to allow traffic in and out as required. The problem is that this also allows Trojans, Spyware and virus programs to do the same! Select the option for uPNP and disable it!
If you have Windows PCs it is a good idea to turn of this feature in Windows. If you need it later you can turn it on by the click of a button. This is a great utility to allow you to turn the UPnP on and off as you require. Check out WWW.GRC.COM for their great Spinrite program, podcasts (Security now) and free utilities.