route - flags

Linux Route Flags (U – Up, G – Gateway, H – Host)

Following is the list of flags and their significance in the routing table :

    U : This flag signifies that the route is up
    G : This flag signifies that the route is to a gateway. If this flag is not present then we can say that the route is to a directly connected destination
    H : This flag signifies that the route is to a host which means that the destination is a complete host address. If this flag is not present then it can be assumed that the route is to a network and destination would be a network address.
    D : This flag signifies that this route is created by a redirect.
    M : This flag signifies that this route is modified by a redirect.