I can not ping from one PC2 (vlan 10) to PC1 (vlan 20) with trunking (ROAS)

[Leerical]

Good morning all,

I've been following a video series that teaches VLANs, trunking, and subinterfaces. However, no matter how much I try to follow along I am not able to replicate the results of the video series. I've tried at least 5 times. My problem starts when I try to configure the router with subnets (encapsulation dot1q, etc). I then create a trunking connection to the switch from the router. Yet, no success in being able to communicate between PC2 (VLAN 10) to PC1 (VLAN 20). Any suggestions?pinging from PC2 to PC1RouterSwitch 1Switch 2

[PaulSmith]

Check if int gig 0/1 is administratively down. It has to be up for int gig 0/0.10 to be up.

[Leerical]

Hey Paul!

Thanks for the reply. Yes, it is up. 

[Leerical]

Router ip int brief (pane)

[Jerome BERTHIER]

Hi

Does each PC ping the IP adress of the router on their vlan ?

If not :

1) verify the netmask of the interface of each PC. You are sharing the same Class C subnet into two /25 subnets. It is a common issue to keep 255.255.255.0 (/24) as netmask...

2) please verify that vlans 10 and 20 are correctly set up :

- sh vlan brie : to verify that both vlans 10 and 20 are present on each switch

- sh run int <name_if> : to verify the config of port switch of each PC and in front of the router

In front of the router, the swith port should look like :

int <name_if>

switchport mode trunk

no shut

! add this if you want to limit vlans

!  switchport trunk allowed vlan 10,20

Regards

Jérôme

[Leerical]

Neither PC's will ping the Router.

2.) Switch 1 does not have vlan 20 on it because the switch port connecting to the next switch is trunked. 

[m.s.rees1]

I can't quite make out your diagrams, but have you added both vlans to all the switches in the path?

Trunk ports can only carry the VLANs that are actually on the switches. Even if you have set them up correctly on the router, you must then add them to all the switches with the following command example:

conf t

vlan 10

exit

This will create the vlan on the switches, ready to be passed along trunk ports. If you have missed a switch and haven't added either of the VLANs, it's not going to work.

Hope that helps. Apologies if I have misunderstood.

[Leerical]

M.S Rees1, you're good. I think I may have thought from earlier post that if the VLAN is connected to a port it won't work. However, I checked, and both VLAN's are on both switches. It's just that on one switch the VLAN isn't assigned to a port. 

[Leerical]

See any issues with this?

[Meheretab Mengistu]

Hi Leerical,

Let's backup a little bit and start from the basics:

VLANs -- are used to create different LANs. Devices on different VLANs are not able to communicate to each other unless you have a layer 3 device. One way of routing traffic between different VLANs is using ROAS as you configured here --> using subinterfaces. If there are switches, as in your case, you will need to have trunk ports to carry multiple VLANs (if you have more than one VLAN). Trunk ports are used to pass traffics from multiple VLANs as far as the VLANs are configured on the switches.

In your case, if you can not ping from PC2 on VLAN 10 to PC1 on VLAN 20, please follow the steps below:

1) Check whether vlan 20 is configured on Switch 2

2) check whether vlan 10 and vlan 20 is configured on Switch 1

3) check if the port between switch 1 and switch 2 is configured as trunk ports

4) check if the port between switch 1 and Router 2 is configured as trunk port on switch 1 side

If you have configured everything and it still not working, please share your configuration for switch 1, switch 2 and router 2.

P.S.:- Please do not forget to rate correct answers and resolve once you find the correct solution.

HTH,

Meheretab

[Leerical]

See any issues with this?

[Meheretab Mengistu]

I do not see any issue with the configuration of trunk ports. Could you share what is configured on the port connected to PC2? Also, please share similar configurations on SW1 as well?

HTH,
Meheretab

[Leerical]

sw1sw2

PC2 is connected to an access port on f0/1

[Meheretab Mengistu]

Please share the output of "sh run" on both switches and the router so that we could look your configuration and guide you in the right direction.

[Leerical]

Switch#show run (Switch 1)

Switch#show running-config

Building configuration...

Current configuration : 1210 bytes

!

version 12.2

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname Switch

!

!

!

!

!

spanning-tree mode pvst

spanning-tree extend system-id

!

interface FastEthernet0/1

switchport access vlan 10

switchport mode access

!

interface FastEthernet0/2

switchport trunk allowed vlan 10,20

switchport mode trunk

!

interface FastEthernet0/3

!

interface FastEthernet0/4

!

interface FastEthernet0/5

!

interface FastEthernet0/6

!

interface FastEthernet0/7

!

interface FastEthernet0/8

!

interface FastEthernet0/9

!

interface FastEthernet0/10

!

interface FastEthernet0/11

!

interface FastEthernet0/12

!

interface FastEthernet0/13

!

interface FastEthernet0/14

!

interface FastEthernet0/15

!

interface FastEthernet0/16

!

interface FastEthernet0/17

!

interface FastEthernet0/18

!

interface FastEthernet0/19

!

interface FastEthernet0/20

!

interface FastEthernet0/21

!

interface FastEthernet0/22

!

interface FastEthernet0/23

!

interface FastEthernet0/24

!

interface GigabitEthernet0/1

switchport mode trunk

!

interface GigabitEthernet0/2

!

interface Vlan1

no ip address

shutdown

______________________________________________________________________________

hostname Switch2

!

!

!

!

!

spanning-tree mode pvst

spanning-tree extend system-id

!

interface FastEthernet0/1

switchport mode trunk

!

interface FastEthernet0/2

!

interface FastEthernet0/3

switchport access vlan 10

switchport mode access

!

interface FastEthernet0/4

!

interface FastEthernet0/5

!

interface FastEthernet0/6

!

interface FastEthernet0/7

!

interface FastEthernet0/8

!

interface FastEthernet0/9

!

interface FastEthernet0/10

!

interface FastEthernet0/11

!

interface FastEthernet0/12

!

interface FastEthernet0/13

!

interface FastEthernet0/14

!

interface FastEthernet0/15

!

interface FastEthernet0/16

!

interface FastEthernet0/17

!

interface FastEthernet0/18

!

interface FastEthernet0/19

!

interface FastEthernet0/20

switchport access vlan 20

!

interface FastEthernet0/21

!

interface FastEthernet0/22

!

interface FastEthernet0/23

!

interface FastEthernet0/24

!

interface GigabitEthernet0/1

!

interface GigabitEthernet0/2

!

interface Vlan1

no ip address

shutdown