How do I translate the output of show ip-route-table ?
Article ID: 166186
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Issue/Introduction
The SG routing table is available from the cli via the command show ip-route-table and via the URL https://<proxy_ip>:<8082>/TCP/route
It is comprised of a row/column listing of destinations and their next hops/gateways. This table is taken from the Free BSD TCP/IP stack
output generated by netstat -nr on FreeBSD.
Resolution
Here is an example:
TCP/IP Routing Table
Routing tables
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 192.168.1.1 UGS 1 86 0:0
127.0.0.1 127.0.0.1 UH 0 2573 loopback
192.168.1 link#2 UC 0 0 0:0
192.168.1.1 ##:##:##:##:##:## UHLW 1 138 0:0 100
192.168.1.2 ##:##:##:##:##:## UHLW 3 129 0:0 201
192.168.1.3 ##:##:##:##:##:## UHLW 1 3781 0:0 1138
Here are the common flag values you may see for this table:
U Up: The route is active.
H Host: The route destination is a single host.
G Gateway: Send anything for this destination on to this remote system, which will figure out from there where to send it.
S Static: This route was configured manually, not automatically generated by the system.
C Clone: Generates a new route based upon this route for machines we connect to. This type of route is normally used for local networks.
W WasCloned: Indicated a route that was auto-configured based upon a local area network (Clone) route.
L Link: Route involves references to Ethernet hardware.
A couple of other noteworthy flags are: (not seen above)
D Dynamic; route created dynamically by routing protocol or icmp redirect
R Host or net unreachable
M Modified: the route was modified by routing protocol or icmp redirect
The USE column provides a count of the number of packets sent using that route.
The REF field gives the current number of active uses of
the route. Connection oriented protocols normally hold on to a single
route for the duration of a connection while connectionless protocols
obtain a route only while sending. This count is an indication of how many connections are
using the route at the moment.
Life/Expire: The number of seconds before the route is deleted from the table.
CLONING NOTE: The use of the L flag indicates that the route has been installed on an active link. In the case of Ethernet, this will result in the
system placing a MAC address in the Gateway field and adding the W flag for 'Was Cloned" when a connection is detected on the Link.
Cloning is a concept unique to BSD network services. The concept refers to on-demand generation(cloning) of host routes. You will note in the example above
that the route 192.168.1 is installed as a "Link" because this network is associated with an Ethernet interface when an ip address/mask
is assigned to that interface. The routes for 192.168.1.1, 192.168.1.2 and 192.168.1.3 are all cloned routes ('W' flag) meaning they were
automatically generated by the system from a "Link" in this case. The generation of the "W" route does require that some traffic be sent
between the SG and the other network node for the route to be generated.
The Interface/Netif column represents the interface on which the entry is associated. If an ip address is placed on an interface then that network will always be associated with
that interface as a "Link" route, even when a bridge is defined.
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