How does one interpret the routing table that is generated by the
netstat -r command?
Assuming you mean Linux:
The table defines the route to be taken based upon the destination address of a connection. The Destination and Genmask fields are combined to produce a subnet of addresses to which a rule applies. On most systems you have a simple routing table like mine, above. A gateway address of "*" implies that the packets will simply be sent out the interface to reach their target destination. Rule 1 for example, is for reaching systems in my local LAN.
A default rule is usually displayed at the bottom, which is the router to which the packets are sent if no other rules match.
If you paste your routing table with specific rules that are confusing, I could provide more detail.