Thanks, I'm getting attempts from about 15 sources. Do I set up a new filter for each & then branch to another filter set?

You would yes, that's one limitation of the 2800's firewall, with the 2820 series you can just add them to an IP object group.

Ok thanks for your help.

Update

I have now upgraded to a 2820n. Can anyone help with setting up a block for whole IP address ranges please?

1 - Create your IP objects (i.e. an object for each person trying to connect)
2 - Create an IP group on the WAN interface and add in your objects (you may need to create a few of these because I believe they are limited to approx 8 ip objects per group)
3 - Create a data filter that is direction WAN -> LAN - add your ip object as the source etc etc and set the rule to block. Make sure you have checked the box to enable the rule and submit it.
4 - Repeat as required for any additional IP groups.

Thanks Dan

When creating the IP objects, can I block an entire IP range; for instance if I get an attempt from someone using a Turkish ISP, I can block the whole ISP's address range?