How do I know if a router can handle multiple static IPs? Is there a protocol or something I should look out for?
Also - how important is it that my router can support IPv6?
I think the techspecs or the manual of your router will tell you. In case they don't, please provide some information about the router you use for me and other users to look it up.
This is an interesting question that may start a longer discussion here.
It would be highly unusual for a router these days to not support static IPs.
Normally if you connect a computer with a static IP to a router (provided the other connection settings match), there is no problem, the router simply wont allocate that IP to any other computers that use DHCP (to avoid conflicts).
You can normally have as many static IP computers connected as the subnet your router serves allows.
Alternatively, some routers will allow you to specify static IPs to give to computers that connect using DHCP. The router will check the MAC address to see if a static IP has been assigned, and if so, give it that IP instead of the one from the pool.
Usually you can set up these static IPs in your router administration interface, although there may be a limit as to how many you can do (typically at least 8). It has the advantage of not having to set up static IPs on the connecting computer, but still be guaranteed to have the same IP each time the computer is connected.
Do you need just /32 IPs or full blocks? What do you need the router to do with the IPs?
As a rule of thumb, most home routers will not support multiple WAN IPs, and if they do, they won't do it well. If your ISP will be providing a routed block, you will need a decent router to handle it. I would suggest a cisco (not linksys), sonicwall, edgemarc, samsung, siemens, netopia, etc. Basically not a home grade router - which means stay away from anything you can buy at best buy or frys. If your ISP will be handing you a bunch of /32 IPs over a bridged connection, then you can just set up a switch and pull them in parallel off the switch using whatever devices you want. This can be done with home grade equipment effectively.
If is best to try and find the documentation for any router you are interested in from the company website if you want to find out what it is capable of.
Alternatively, many routers can support alternate firmware such as DDWRT, which can handle multiple IP addresses. The DDWRT website has a list of routers it works on.