Does anybody know how to stop this and why they do it?
I check my site search logs (nextopia is who we use for search) and it is flooded by thousands of searches for random products by a few different ip addressses. I block the ip addresses but new ones just show up the next day. How can i stop it, and what do they do it for

here are some example searches

dgn3500-na
dgn3500-100nas
dgn3500na
dgn3500100nas
dgn3500
mc00005
c11ca25231
c11ca67201
b-510dn
scx4623fxaa
scx4623f
scx-4623f/xaa
scx-4623f