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Can't ping vlans from Cisco 4500 as vtp client

Dan_17717
Level 1
Level 1

I have a Cisco 3560x as a vtp server and the 4500 and 2960s as vtp clients.  All the vlans have been propagated.  For some reason, I'm unable to ping certain vlans from the 4500.  All the 2960s are coming off the 4500.  The 2960s are able to ping vlans with the exception of 1 vlan which is 10.100.1.x. The 10.100.1.x switch is coming off the 3560x via virtual interface vlan 100 (10.100.1.1/24).  From the 3560x, I have no problem pinging all the 10.100.1.x devices.  However, from the 4500 and 2960s I'm unable to.  Is there something in the 4500 that I need to config for this to work?  Let me know if you need more info.

Thanks

54 Replies 54

The PCs connected to the 4500 are able to ping all the virtual interface of the vlans (10,16,100).  It can also ping devices in vlan 16, 10.  The only exception is devices in vlan100.

I just don't understand why I can't even ping the virtual interface of vlans 10,16,100 if it's all propapated to the 4500 from 3560x while the 2960s are able to.  All the PCs are able to ping it vlans.

ip default-gateway is 10.40.1.2 /22

no ip routing enable

Can you post the port configurations for the links interconnecting the switches?

From the 4500 --> 3560x   switchport trunk encapsulation dot1q

                                       switchport mode trunk

                     --> 2960s   switchport mode trunk encapsulation dot1q

                                      switchport mode trunk

From the 3560x --> 4500  switchport mode trunk encapsulation dot1q

                                      switchport mode trunk

From all 2060s --> 4500   switchport mode trunk

Cisco 3560x has ip routing enable with ospf.  Do I need to have ip routing enable with ospf in the 4500?  Right now, the 3560x is the vtp server and the 4500 is the vtp client.

If all of the SVIs reside on the 3560x - then you dont need routing enabled on the 4500.

Dan,

1. Are we getting any arp entry for SVI ips in 4500  ?

2. If step 1 show incomplete. Do we have any native vlan configured in trunk port to 3560 ? if not try configuring the managment vlan as native and verify

Regards

The only arp entry is from vlan1.  How do I go about configuring a native vlan in trunk port to 3560?  Would it disrupt the network?

Dan,

Can we try this command from 4500 global config mode and verify the status ?

no vlan dot1q tag native

regards

Partha

Will this cause connection issue with the other switches?  We are in production and I don't want to make any changes that might cause a disruption in the network.

Here's what I got from the 4500.  I have not enter the above command.

sh vlan dot1q tag native

dot1q native vlan tagging is disabled globally

--so native vlan tagging state is disabled on all interfaces.

Dan,

i believe we are able to reach the SVI from 2960

1. Initiate ping from 4500 and 2960 to SVI, then compare the arp table of 2960 with 4500 to find out what are the difference in enteries in arp table?

2.  Do a below manual configuration of native vlan on the trunk port of 4500 (although this is enable by default for vlan 1) and try to verify.

  switchport  trunk native vlan 1

3. If step 2 fails , First clear arp table and then  intiate debug arp in both 4500 and 3560  to verify arp request /response status between 4500 and 3560 when we try to reach the SVI of 3560. This will give fair idea where we are getting stuck.

you can perform these step in off busines hours although execution of these command. will not have any down time.

Regards

Partha

Hello

Can you make sure on all switches apart from the 3560 that
1) ip routing is DISABLED
2) vlans are actually propagated in vtp database of all switches and all vlans are allowed to cross the trunks interconnects of these switches

Sh vtp status
Sh vlan brief
Sh int trunk
Sh ip routing (if applicable)

Res
Paul


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Kind Regards
Paul

All the vlans from the 3560x have propagated to the 4500 and 2960s. 

3560x- vtp server

4500 - vtp client

2960s - vtp client

no ip routing enable on 4500 and 2960s.  Default gateway is pointed to vlan 1 of 3560x.

When telneting into vlan1 of 4500, I cannot ping any SVIs other than vlan1.  The 2960s has no problem.

Is there any other config that needs to be set on vlan 1 of the 4500 since its also a Layer 3 device?  The ports are trunk with the 3560x.

This is what I get when doing a sh ip route from the 4500.

C 10.40.0.0/22 is directly connected, Vlan 1

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