I have a Cisco 3650 with inter-vlan routing enabled. All vlans reach each other with no problems. The problem appeared when I connected an unmanaged switch to an interface on the cisco. I set up a vlan with the same ip range of the unmanaged switch, I also set up an interface vlan in the same ip range of the unmanaged switch. Now, when i'm on the exec mode on the cisco switch, i can reach all devices on the unmanaged switch, however, from any other valn, I cannot.
no aaa new-model
system mtu routing 1500
vtp domain h873.eur.nsroot.net
vtp mode transparent
ip subnet-zero
ip routing
vlan 116
name PROD_VLAN_111
!
vlan 120,200
!
vlan 211
name MGMT_PHY_211
!
vlan 212
name MGMT_APP_212
!
!
!
!
interface GigabitEthernet0/1
switchport access vlan 211
switchport mode access
!
interface GigabitEthernet0/2
switchport access vlan 212
switchport mode access
!
interface GigabitEthernet0/3
switchport access vlan 116
switchport mode access
!
interface GigabitEthernet0/11
description Connection to Unmanaged Switch
switchport access vlan 200
switchport mode access
!
interface GigabitEthernet0/14
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/15
!
interface GigabitEthernet0/16
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/17
!
interface GigabitEthernet0/18
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/19
!
interface GigabitEthernet0/20
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/21
!
interface GigabitEthernet0/22
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/23
!
interface GigabitEthernet0/24
switchport trunk encapsulation dot1q
switchport mode trunk
interface Vlan1
no ip address
!
interface Vlan116
ip address 172.16.116.1 255.255.255.0
!
interface Vlan120
ip address 10.11.120.1 255.255.255.0
!
interface Vlan200
ip address 192.168.1.100 255.255.255.0
!
interface Vlan211
ip address 10.11.211.1 255.255.255.0
!
interface Vlan212
ip address 10.11.212.1 255.255.255.0
!
router ospf 100
log-adjacency-changes
redistribute connected subnets
network 172.16.116.0 0.0.0.255 area 0
!
ip default-gateway 192.168.1.165
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.1.1
ip http server
ip http secure-server
!
So for example, if i run "ping 192.168.1.100 source 10.11.211.1" the pings are fine, but if i run "ping 192.168.1.1 source 10.11.211.1"
it is not successful.
Any help would be much appreciated.
Switch#ping 192.168.1.1
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/8 ms
Switch#ping 192.168.1.1 source 10.11.211.1 Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
Packet sent with a source address of 10.11.211.1
.....
Success rate is 0 percent (0/5)
Switch#ping 192.168.1.100 source 10.11.211.1
Packet sent with a source address of 10.11.211.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/9 ms
Best Answer
If the hosts on the unmanaged switch have a gateway set to
192.168.1.1
, then traffic from those hosts to a different network will be sent to that router, and if that router needs to send back to the switch on that network, it will not. Routers have split-horizon, meaning that they will not route back to the same network on which a packet is received.You want the inter-VLAN routing to happen on the switch, not the WAN router, so the switch must be the gateway for all the hosts. The WAN router should inject the default route into OSPF, and you should not have a default route on the switch.