This sets up a route to a specific host. What this is typically used for is to route traffic for one particular host differently than other hosts on his subnet. For example:
ip route 10.1.0.0 255.255.255.0 10.2.1.1
ip route 10.1.0.11 255.255.255.255 10.2.2.1
All traffic for subnet 10.1.0.0/24 is routed through 10.2.1.1. However, all traffic for host 10.1.0.11 (as indicated by his 255.255.255.255 mask) is routed through 10.2.2.1. May be the host 10.1.0.11 is special and deserves to have its traffic routed throgh a dedicated link. Remember the router always picks the matching route with the longest subnet mask to use. This is true no matter the order of the routes in the table, or source (routing protocol or static) of the route.
Another use for this trick is to "blackhole" undesirable destinations for short periods of time. For example, if you find someone visiting a porno web site at say, 10.99.99.99, you can use the following command to blackhole him:
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...