I have a weird problem with my switch.
I have an ospf and I wanted to add 2 networks:
network 172.27.3.0 0.0.0.255 area 0.0.0.0
network 172.27.7.0 0.0.1.255 area 0.0.0.0
But in my run config is no write network 172.27.7.0 0.0.1.255 area 0.0.0.0 but network 172.27.6.0 0.0.1.255 area 0.0.0.0.
network 172.27.3.0 0.0.0.255 area 0.0.0.0 is good
I can remove network 172.27.6.0 0.0.1.255 area 0.0.0.0 with a "no" but when I write network 172.27.7.0 0.0.1.255 area 0.0.0.0, it come back.
I already tested :
remove network 172.27.6.0 0.0.1.255 area 0.0.0.0 and wr but my problem is still here
remove network 172.27.6.0 0.0.1.255 area 0.0.0.0 and reload the switch but my problem is still here
when you config NET under ospf with summary prefix the router will not advertise the summary it will advertise the prefix of interface UP within the summary range,
here you have link have 172.27.6.0
and hence the OSPF advertise it.
for summary you need area range command between Area (config in ABR) to advertise the range.
I believe OP Looking why he is not seeing 172.27.7.0/23 in the config when he configured the config in the OSPF network.
when he look show run ( he only seeing 172.27.6.0/23 instead 172.27.7.0/23)
or am i missing here something ?
The behavior you are experiencing is the OSPF process only permits network statements which list a network ID and wildcard mask. Given 172.27.7.0 0.0.1.255 , the network ID of 172.27.7.0/23 is 172.27.6.0 . OSPF is making the correction for you.
It is not because the network octet is odd. You could for example use:
network 172.27.7.0 0.0.0.255 area 0
...which would remain unchanged in the running configuration.