Introduction to Route Summarization

Lessons Discussion
6

Hii Rene,

1st query:
no auto-summary command is issued to disable summary.
and to enable summary can we use R1(config-router)#auto-summary command instead of using R1(config-if)#ip summary-address rip 172.16.0.0 255.255.0.0

2nd Query:

R1#
RIP: sending v2 update to 224.0.0.9 via GigabitEthernet0/1 (192.168.12.1)
RIP: build update entries
        172.16.0.0/24 via 0.0.0.0, metric 1, tag 0
        172.16.1.0/24 via 0.0.0.0, metric 1, tag 0
        172.16.2.0/24 via 0.0.0.0, metric 1, tag 0
        172.16.3.0/24 via 0.0.0.0, metric 1, tag 0

In above RIP update why network is advertising via"0.0.0.0" ?

Regards,
Chandra