07-05-2022 06:56 AM - last edited on 07-07-2022 09:31 AM by Translator
Hi all, i am hoping to get your assistance ...
we have a flat network where EVERYTHING runs on VLAN1, even to CE interface - oh boy!
please forgive me in advance as i am not very familiar with routing...
presently, i have a c9200 switch, our CE connects to port 37.OSPF, Routing Protocols
vlan 1
ip address 192.160.84.1 -->> CE device IP ...84.6
all switchport interfaces are defaulted to vlan 1
sh ip cef shows my next hop to 84.6 on g1/0/37
introducing OSPF
ip routing
router ospf 1
router-id 1.1.1.15
network 192.160.84.0 0.0.0.255 area 0 - more networks to follow, but i wanted to get things working with the current network.
removed IP from VLAN 1
Added
interface GigabitEthernet1/0/48
no switchport
ip address 192.160.84.1 255.255.255.0
no ip route-cache
ip route 0.0.0.0 0.0.0.0.0 192.160.84.6
i can see my adjacencies come up and are able to ping across the WAN from the switch, but i am not able to get an IP or can do anything from within the LAN.
hoping to can see something i am missing...
Many thanks in advance!
Hamid
Solved! Go to Solution.
07-05-2022 09:21 AM - edited 07-05-2022 09:22 AM
See my original response.
If you have moved the subnet 192.160.84.0/24 it now only exists between the L3 port on the switch and the router.
If you want your clients to have connectivity then either use another subnet for vlan 1 and add that subnet to OSPF or better yet use a new vlan on the switch and create an SVI for it and then add the subnet to OSPF.
You cannot use 192.160.84.0/24 for your clients now.
Jon
07-05-2022 07:13 AM
i can see my adjacencies come up and are able to ping across the WAN from the switch,
you mean OSPF up and running ?
but i am not able to get an IP or can do anything from within the LAN.
IP you need to get from DHCP server, where DHCP Located ? you need more information to provided, when you mention anything can not do from your LAN ? what thngs ?
07-05-2022 07:19 AM
That isn't going to work.
The SVI for vlan 1 is accessible to all ports as are all SVIs ie. you could create an SVI for vlan 10 and then you can allocate ports into vlan 10 on the switch and they can access the SVI.
But you have moved the IP to a L3 routed port so none of the L2 ports on the switch can use that as their gateway because it is not accessible.
The 192.160.84.0/24 now terminates on that L3 port and nothing else on the switch can now be in the same subnet.
Jon
07-05-2022 07:43 AM - last edited on 07-07-2022 09:37 AM by Translator
before remove VLAN IP
SW-CE/R
all client in SW will use VLAN IP for routing packet and use it to forward the pocket to CE/R
after remove VLAN IP
all client now need L3 device to routing packet and here the router must do routing packet for these client.
here you do one mistake
config interface between two SW and CE/R is L3 with
add no switch port
command.
so
finally
SW have many VLAN and you want SW to DO inter-VLAN and advertise the VLAN SVI IP to CE do
run
ip routing
!
config SVI IP for each VLAN
!
interface between SW-CE/R
no switch port
ip add <subnet /30 different than any SVI IP>
!
OSPF
net SVI IP
net subent /30 of interface connect SW-CE/R
SW have many VLAN and you want R/CE to inter-VLAN
run
no ip routing
!
NOT config SVI IP for each VLAN
!
interface between SW-CE/R
mode trunk
allow all VLAN you need
!
NO NEED OSPF
in CE/R
run
interface between SW-CE/R
subinterface for each VLAN in SW
07-05-2022 08:03 AM
if you assigned IP to L3 port (port 48) your other end device in same network should connected to port 48. not to 37. as per my understanding. also if you can share some basic diagram with port numbers, that will give us hint.
07-05-2022 08:06 AM - last edited on 07-07-2022 09:39 AM by Translator
hi All, thank you for your feed back.
i believe i've done most of what you all have described.
assigned IP on routed interface:
interface GigabitEthernet1/0/48
description Bell Uplink - next hop 192.162.84.6
no switchport
ip address 192.160.84.1 255.255.255.0
no ip route-cache
shutdown
removed the IP from VLAN1
no ip address
move my WAN cable to port 48
OSPF
router ospf 1
router-id 1.1.1.15
network 192.160.84.0 0.0.0.255 area 0
default route
ip route 0.0.0.0 .0.0.0.0 192.160.84.6
at this point i can see routes with "show ip route"
although, i wasnt able to get address from DHCP server that is local to me. or get at any resources from my local LAN
i am able to ping across the WAN to other networks from the switch since my routes are up.
my problem is that i am not getting connectivity from within the local network after configuring the above, WAN is okay. i had to revert back my changes.
07-05-2022 08:17 AM - edited 07-05-2022 08:28 AM
either the inter-vlan in SW or CE/R see my above comment
07-05-2022 08:18 AM - edited 07-05-2022 08:19 AM
still i got back to my orginal question, where is DHCP ? you are not giving information to suggest ?
@Jon Marshall given another direction, that not going to work if the VLAN1 is down, and you looking DHCP address from VLAN1, every post connected to belong to VLAN1
can you post show run
07-05-2022 09:03 AM
Hi Balaji.Bandi,
the DHCP is locally presented, connected to VLAN1. i have not introduced any new VLANs. simply working with VLAN1. all my SW ports are on VLAN1
07-05-2022 09:21 AM - edited 07-05-2022 09:22 AM
See my original response.
If you have moved the subnet 192.160.84.0/24 it now only exists between the L3 port on the switch and the router.
If you want your clients to have connectivity then either use another subnet for vlan 1 and add that subnet to OSPF or better yet use a new vlan on the switch and create an SVI for it and then add the subnet to OSPF.
You cannot use 192.160.84.0/24 for your clients now.
Jon
07-05-2022 09:52 AM
thanks for this Jon. that makes sense. i will have to go back to the drawing board and i now have to inventory all the static devices, servers, printers etc...
i then have to create VLANs accordingly for static and dynamic networks and other configs.
Thanks you to everyone with your guidance!
Hamid
07-05-2022 10:04 AM
Alternatively could keep all the clients etc. on 192.160.84.0/24 and just use a new IP subnet for the L3 connection between the switch and the router.
Jon
07-05-2022 10:12 AM
i thought of this, but i don't don't feel like fighting with our ISP. i still need to build out multiple VLANs anyway. so i will go back to the drawing board :(...
thanks again Jon!
07-05-2022 09:40 AM
can you post show run
07-05-2022 10:08 AM - last edited on 07-07-2022 09:41 AM by Translator
interface Vlan1
ip address 192.160.84.1 255.255.255.0 <<<- here the IP is conflict, only change it to other IP
!
interface Vlan48
description 9270 Wired - DHCP
ip address 172.20.48.1 255.255.255.0
ip helper-address 192.168.20.14
!
interface GigabitEthernet1/0/48
description Bell Uplink - next hop 192.162.84.6
no switchport
ip address 192.160.84.1 255.255.255.0
that only what you need
inter-VLAN in SW
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