Here comes details
1. Network diagram
2. R1 configuration
/interface ethernet
set [ find default-name=ether1 ] name=ether1-OUT1
set [ find default-name=ether2 ] name=ether2-R2
/routing ospf instance
set [ find default=yes ] distribute-default=if-installed-as-type-1 name=R1 \
redistribute-connected=as-type-1 router-id=255.255.255.255
/ip address
add address=192.168.0.2/24 interface=ether1-OUT1 network=192.168.0.0
add address=10.255.0.6/30 interface=ether2-R2 network=10.255.0.4
add address=192.168.90.1/24 interface=ether4 network=192.168.90.0
/ip route
add distance=1 gateway=192.168.0.1
/routing ospf network
add area=backbone network=10.255.0.4/30
/system identity
set name=R1
3. R2 configuration
/interface ethernet
set [ find default-name=ether5 ] name=ether5-OUT2
set [ find default-name=ether6 ] name=ether6-R1
set [ find default-name=ether7 ] name=ether7-R3
/routing ospf area
set [ find default=yes ] name=R2
/routing ospf instance
set [ find default=yes ] distribute-default=if-installed-as-type-1 \
metric-default=100 name=R2 redistribute-connected=\
as-type-1
/ip address
add address=192.168.88.1/24 interface=ether8 network=192.168.88.0
add address=10.255.0.1/30 interface=ether7-R3 network=10.255.0.0
add address=10.255.0.5/30 interface=ether6-R1 network=10.255.0.4
add address=192.168.1.23/24 interface=ether5-OUT2 network=192.168.1.0
/ip route
add check-gateway=ping distance=200 gateway=192.168.1.1
/routing ospf network
add area=R2 network=10.255.0.0/30
add area=R2 network=10.255.0.4/30
/system identity
set name=R2
4. Simple R3
/interface ethernet
set [ find default-name=ether4 ] name=ether4-R2
/routing ospf instance
set [ find default=yes ] name=R3 redistribute-connected=as-type-1
/ip address
add address=192.168.89.1/24 interface=ether2 network=192.168.89.0
add address=10.255.0.2/30 interface=ether4-R2 network=10.255.0.0
/routing ospf network
add area=backbone network=10.255.0.0/30
/system identity
set name=R3
But on R2 we see
[admin@R2] > routing ospf neighbor pr
0 instance=R2 router-id=10.255.0.2 address=10.255.0.2 interface=ether7-R3
priority=1 dr-address=10.255.0.2 backup-dr-address=10.255.0.1 state="Full"
state-changes=5 ls-retransmits=0 ls-requests=0 db-summaries=0
adjacency=13m49s
1 instance=R2 router-id=255.255.255.255 address=10.255.0.6 interface=ether6-R1
priority=1 dr-address=10.255.0.6 backup-dr-address=10.255.0.5 state="Full"
state-changes=6 ls-retransmits=0 ls-requests=0 db-summaries=0
adjacency=13m54s
[admin@R2] >
But R2 uses it's own default gw!
[admin@R2] > ip rou pr
Flags: X - disabled, A - active, D - dynamic,
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme,
B - blackhole, U - unreachable, P - prohibit
# DST-ADDRESS PREF-SRC GATEWAY DISTANCE
0 A S 0.0.0.0/0 192.168.1.1 200
1 ADC 10.255.0.0/30 10.255.0.1 ether7-R3 0
2 ADC 10.255.0.4/30 10.255.0.5 ether6-R1 0
3 ADo 192.168.0.0/24 10.255.0.6 110
4 ADC 192.168.1.0/24 192.168.1.23 ether5-OUT2 0
5 DC 192.168.88.0/24 192.168.88.1 ether8 255
[admin@R2] >
Just for info
[admin@R2] > routing ospf route pr
# DST-ADDRESS STATE COST GATEWAY INTERFACE
0 0.0.0.0/0 imported-ext-1 100
1 10.255.0.0/30 intra-area 10 0.0.0.0 ether7-R3
2 10.255.0.4/30 intra-area 10 0.0.0.0 ether6-R1
3 192.168.0.0/24 ext-1 30 10.255.0.6 ether6-R1
4 192.168.1.0/24 imported-ext-1 100
[admin@R2] >