Route flags in ODM 1

[unixfreak]

Hi, wondering a bit where route flags like 'c' (cloning) are stored? It's not in the stanza for the relevant ODM entry, how is this flag set and why? What's it used for?

Thanks

 

[unixfreak]

And now that I'm here, can someone explain these entries to me please, I think they're related to each other:

172.23.130.40 172.23.133.120 UGHW 3 0 en4 - - -
172.23.133.0 172.23.133.222 UHSb 0 0 en4 - - - =>
172.23.133/24 172.23.133.222 U 11 5402722 en4 - - -
172.23.133.222 127.0.0.1 UGHS 0 2 lo0 - - -

 

[mrn]

Route cloning allows a host route to be created for every host that a system communicates with.

When network traffic is about to be sent, a search is done of the routing table to find a route to that host. If a specific host route is found, it will be used. If a specific host route is not found, a network route or the default route may be found. If the route that is found has the cloning flag, 'c', set, a host route for the destination will be created using the gateway from the route that is being cloned. Subsequent routing table searches for that destination will find the cloned host route. Cloned routes have the 'W' flag set. These routes will time out and be deleted from the routing table if they are unused for route_expire minutes. You can modify route_expire by using the no command.

The route cloning feature is used mainly by the path MTU discovery protocol within AIX to allow it to keep track of path MTU information for every destination it communicates with. If the network options tcp_pmtu_discover or udp_pmtu_discover (settable with the no command) are 1, the cloning flag is turned on for all network routes on the system.

              A
                   An Active Dead Gateway Detection is enabled on the route. This field only applies to
                   AIX 5.1 or later.
              U
                   Up.
              H
                   The route is to a host rather than to a network.
              G
                   The route is to a gateway.
              D
                   The route was created dynamically by a redirect.
              M
                   The route has been modified by a redirect.
              L
                   The link-level address is present in the route entry.
              c
                   Access to this route creates a cloned route.
              W
                   The route is a cloned route.
              1
                   Protocol specific routing flag #1.
              2
                   Protocol specific routing flag #2.
              3
                   Protocol specific routing flag #3.
              b
                   The route represents a broadcast address.
              e
                   Has a binding cache entry.
              l
                   The route represents a local address.
              m
                   The route represents a multicast address.
              P
                   Pinned route.
              R
                   Host or net unreachable.
              S
                   Manually added.
              u
                   Route usable.
              s
                   The Group Routing stopsearch option is enabled on the route.

hope this helps

Mike

"Whenever I dwell for any length of time on my own shortcomings, they gradually begin to seem mild, harmless, rather engaging little things, not at all like the staring defects in other people's characters."

 

[unixfreak]

Thanks Mike, helpful description I've spent the whole day getting my head around a messed up routing table.

Thanks
Henrik