G RTF_GATEWAY Destination requires forwarding by intermediary
H RTF_HOST Host entry (net otherwise)
I RTF_IFSCOPE Route is associated with an interface scope
+i RTF_IFREF Route is holding a reference to the interface
L RTF_LLINFO Valid protocol to link address translation
M RTF_MODIFIED Modified dynamically (by redirect)
m RTF_MULTICAST The route represents a multicast address