Unable to communicate with new stack by management IP address

stevebennettnz1 · ‎07-27-2015

I've got 2 existing 3750 switch stacks connected to each other using a port channel, call them stack A and stack B and these existing stacks have been running fine for quite some time

I've connected new stack C (2960 switches) to stack B, also via a port channel

Connected devices can happily communicate on their respective VLANs to other devices on the other stacks

But I'm unable to connect to the management ip address that I've created on the new stack from either of the other 2 stacks

The management IP is assigned to a vlan just like on the other stacks, and the port channel is configured as a trunk (also with the same configuration as the port channel between stacks A and B, but with a different port channel ID number of course)

Can anyone offer any suggestions for troubleshooting?

Part of new stack C configuration:

interface Vlan96
ip address 192.168.96.248 255.255.255.0
ip default-gateway 192.168.96.250
ip route 0.0.0.0 0.0.0.0 192.168.96.250

interface Port-channel9
description uplink to stack B
switchport mode trunk

interface GigabitEthernet1/0/1
description uplink to stack B
switchport mode trunk
channel-group 9 mode on

interface GigabitEthernet2/0/1
description uplink to stack B
switchport mode trunk
channel-group 9 mode on

Reza Sharifi · ‎07-27-2015

Since the new stack is operating at layer-2, you don't need both:

ip default-gateway 192.168.96.250
ip route 0.0.0.0 0.0.0.0 192.168.96.250

try deleting the ip route 0.0.0.0 0.0.0.0 192.168.96.250 and test again

Having both commands should not cause disconnect but lets try and remove one and test

HTH

stevebennettnz1 · ‎07-27-2015

Hi Reza, thanks for your advice

I've removed that part of the config, but unfortunately I still can't telnet or ping the management IP

Umesh Shetty · ‎07-27-2015

Hi Steve,

Can you post the portchannel and member interface configuration of the Stack B also.

Are the connected devices in the same Vlan 96 or different ? .

All I want to verify here is if the other end portchannel config also has the Vlan96 allowed on the trunk.

Regards

Umesh

stevebennettnz1 · ‎07-28-2015

Hi Umesh, here is the port channel config of stack B, and also the output from the "show cdp neighbors detail" command on stack B. As you can see in the output, stack B is aware of stack C via CDP, but it can't enumerate the management IP for some reason. None of the connected devices are in VLAN 96, but I'll have a go at connecting a laptop to stack C on VLAN96 and see if it can communicate with the other stacks and devices. Thanks, Steve

interface Port-channel9
description temp uplink to 2960 stack C
switchport trunk encapsulation dot1q
switchport mode trunk

interface FastEthernet2/0/13
description temp uplink to 2960 stack C
switchport trunk encapsulation dot1q
switchport mode trunk
channel-group 9 mode on

interface FastEthernet4/0/11
description temp uplink to 2960 stack C
switchport trunk encapsulation dot1q
switchport mode trunk
channel-group 9 mode on

AAC_GFR_01G#show cdp neighbors detail
-------------------------
Device ID: CIP_GFR_01
Entry address(es):
Platform: cisco WS-C2960X-48FPS-L, Capabilities: Switch IGMP
Interface: FastEthernet4/0/11, Port ID (outgoing port): GigabitEthernet2/0/1
Holdtime : 136 sec

Version :
Cisco IOS Software, C2960X Software (C2960X-UNIVERSALK9-M), Version 15.0(2)EX5, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2014 by Cisco Systems, Inc.
Compiled Fri 21-Feb-14 05:54 by prod_rel_team

advertisement version: 2
Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF0102250900000000000040A6E86C6B00FF0000
VTP Management Domain: ''
Native VLAN: 1
Duplex: full
Management address(es):

-------------------------
Device ID: CIP_GFR_01
Entry address(es):
Platform: cisco WS-C2960X-48FPS-L, Capabilities: Switch IGMP
Interface: FastEthernet2/0/13, Port ID (outgoing port): GigabitEthernet1/0/1
Holdtime : 136 sec

Version :
Cisco IOS Software, C2960X Software (C2960X-UNIVERSALK9-M), Version 15.0(2)EX5, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2014 by Cisco Systems, Inc.
Compiled Fri 21-Feb-14 05:54 by prod_rel_team

advertisement version: 2
Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF0102250900000000000040A6E86C6B00FF0000
VTP Management Domain: ''
Native VLAN: 1
Duplex: full
Management address(es):

stevebennettnz1 · ‎07-28-2015

Hi guys, it turned out to be a mistake on my part - even though I had configured a "VLAN interface", it looks like the VLAN itself didn't actually exist. When I configured one of the ports with access to VLAN96, it created the VLAN on the fly (as below), and then the management IP started to respond. I didn't realise that there are 2 parts to setting up the management VLAN. Thanks very much for your help. Regards, Steve

CIP_GFR_01#conf t
Enter configuration commands, one per line. End with CNTL/Z.
CIP_GFR_01(config)#int gig2/0/48
CIP_GFR_01(config-if)#switchport access vlan 96
% Access VLAN does not exist. Creating vlan 96
CIP_GFR_01(config-if)#^Z
Jul 28 21:00:03.378: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan96, changed state to up

Umesh Shetty · ‎07-29-2015

Hi Steve,

Good to know that your problem is now solved,

Regards

Umesh