Good morning.

Could someone explain to me the meaning of the flags in the routing table?

For example if you check the output of netstat -nr you will have lines like this:

default          UGSc           56        3     en0

So this route for example has UGSc as flags.

The complete list of flags should be the following:

1   RTF_PROTO1  Protocol specific routing flag #1
2   RTF_PROTO2  Protocol specific routing flag #2
3   RTF_PROTO3  Protocol specific routing flag #3
B   RTF_BLACKHOLE   Just discard pkts (during updates)
b   RTF_BROADCAST   The route represents a broadcast address
C   RTF_CLONING     Generate new routes on use
c   RTF_PRCLONING   Protocol-specified generate new routes on use
D   RTF_DYNAMIC     Created dynamically (by redirect)
G   RTF_GATEWAY     Destination requires forwarding by intermediary
H   RTF_HOST    Host entry (net otherwise)
L   RTF_LLINFO  Valid protocol to link address translation
M   RTF_MODIFIED    Modified dynamically (by redirect)
R   RTF_REJECT  Host or net unreachable
S   RTF_STATIC  Manually added
U   RTF_UP  Route usable
W   RTF_WASCLONED   Route was generated as a result of cloning
X   RTF_XRESOLVE    External daemon translates proto to link address
Y   RTF_PROXY     Proxying; cloned routes will not be scoped

Well, some of them are easy to understand, other are more obscure to me...

Can someone eplain me what they mean please? Thanks very much



Browse other questions tagged .