Why is R1 giving these error messages?
IP-EIGRP(Default-IP-Routing-Table:400): Neighbor 192.168.2.1 not on common subnet for FastEthernet1/0
IP-EIGRP(Default-IP-Routing-Table:400): Neighbor 192.168.2.2 not on common subnet for FastEthernet1/0
R1 is able to ping every router.
Configs:
R1 routing table
20.0.0.0/29 is subnetted, 1 subnets
D 20.20.20.0 [90/30720] via 192.168.1.2, 00:06:56, FastEthernet1/0
10.0.0.0/29 is subnetted, 1 subnets
C 10.10.10.0 is directly connected, FastEthernet0/0
192.168.1.0/29 is subnetted, 1 subnets
C 192.168.1.0 is directly connected, FastEthernet1/0
192.168.2.0/29 is subnetted, 1 subnets
D 192.168.2.0 [90/30720] via 10.10.10.2, 00:06:56, FastEthernet0/0
R1
!
!
!
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
!
!
ip cef
no ip domain lookup
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
!
interface FastEthernet0/0
ip address 10.10.10.1 255.255.255.248
duplex auto
speed auto
!
interface FastEthernet1/0
ip address 192.168.1.1 255.255.255.248
duplex auto
speed auto
!
router eigrp 400
network 10.10.10.0 0.0.0.7
network 192.168.1.0 0.0.0.7
no auto-summary
!
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous
line aux 0
exec-timeout 0 0
privilege level 15
logging synchronous
line vty 0 4
login
!
!
end
R2
!
!
!
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R2
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
!
!
ip cef
no ip domain lookup
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
!
interface FastEthernet0/0
ip address 20.20.20.1 255.255.255.248
duplex auto
speed auto
!
interface FastEthernet1/0
ip address 192.168.1.2 255.255.255.248
duplex auto
speed auto
!
router eigrp 400
network 20.20.20.0 0.0.0.7
network 192.168.1.0 0.0.0.7
no auto-summary
!
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous
line aux 0
exec-timeout 0 0
privilege level 15
logging synchronous
line vty 0 4
login
!
!
end
R3
!
!
!
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R3
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
!
!
ip cef
no ip domain lookup
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
!
interface FastEthernet0/0
ip address 10.10.10.2 255.255.255.248
duplex auto
speed auto
!
interface FastEthernet1/0
ip address 192.168.2.1 255.255.255.248
duplex auto
speed auto
!
router eigrp 400
network 10.10.10.0 0.0.0.7
network 192.168.2.0 0.0.0.7
no auto-summary
!
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous
line aux 0
exec-timeout 0 0
privilege level 15
logging synchronous
line vty 0 4
login
!
!
end
R4
!
!
!
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R4
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
!
!
ip cef
no ip domain lookup
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
!
interface FastEthernet0/0
ip address 20.20.20.2 255.255.255.248
duplex auto
speed auto
!
interface FastEthernet1/0
ip address 192.168.2.2 255.255.255.248
duplex auto
speed auto
!
router eigrp 400
network 20.20.20.0 0.0.0.7
network 192.168.2.0 0.0.0.7
no auto-summary
!
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous
line aux 0
exec-timeout 0 0
privilege level 15
logging synchronous
line vty 0 4
login
!
!
end
Best Answer
EDIT:
EIGRP uses multicast hello packets in order to communicate to other EIGRP neighbors. EIGRP generates the not on common subnet error message when it receives an EIGRP hello packet sourced from an IP address on a subnet that is not configured on its receiving interface.
These are the general cause for this error message:
In order to troubleshoot this issue, check these items:
I would suggest check physical connection and configuration.