08-30-2015 12:06 PM - edited 03-08-2019 01:34 AM
Hi,
I am unable to ping/telnet to one of our cisco switches model 3560, switch is working fine except I cannot access it.It's also showing as neighbor in show cdp neighbor command from neighbor switch.
show arp is not showing the entry for switch IP, when I start pinging it, it only shows incomplete entry in arp table.
configuration on both switches is very simple, ports are just configured as trunk
#switchport mode trunk
#switchport nonegotiate
I attached some output commands from neighbor switch: connected on Gi1/0/48
Solved! Go to Solution.
08-31-2015 04:52 AM
it's look like you got some kind of configuration problem there, you will have to get console access to solve it.
08-30-2015 11:44 PM
Hi Shazad,
Can you please share with us more information?
show ip route 10.100.25.3
show mac-address table int gi 1/0/48
Thanks,
Omer Shtivi
08-31-2015 12:23 AM
Hi Omer,
show mac command is not running on cisco 3850
10.100.25.2 is mgmt ip of problematic switch, 10.100.25.3 is mgmt ip of router.
CISCO3850#sh ip route 10.100.25.2
Routing entry for 10.100.25.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Routing Descriptor Blocks:
* directly connected, via Vlan10
Route metric is 0, traffic share count is 1
CISCO3850#sh ip route 10.100.25.3
Routing entry for 10.100.25.3/32
Known via "static", distance 1, metric 0
Routing Descriptor Blocks:
* 10.10.10.1
Route metric is 0, traffic share count is 1
Thanks
Shahzad
08-31-2015 12:52 AM
If you see two different command's output below; in first Gi1/0/48 is showing in native vlan 1 whereas in 2nd output its showing "directly connected, via Vlan10"
08-31-2015 01:22 AM
can you send show mac-address table int gi1/0/48?
08-31-2015 01:44 AM
Please find the output below;
08-31-2015 04:35 AM
Two things,
First you keep looking for 10.100.25.2 and pinging it while at the CDP neighbor the switch claims it's at address 10.100.25.3:
"Management address(es):
IP address: 10.100.25.3 "
Second it's seems like vlan 10 is not on the trunk on the other side, you don't learn any mac addresses on this vlan on interface gi1/0/48.
The most common reason is that the vlan doesn't exsist on the other switch. Someone configured interface vlan 10, but didn't added the command vlan 10
Best regards,
Omer Shtivi
08-31-2015 04:47 AM
Let me explain you my connectivity:
Router -------- Switch A--------Trunk Link-----------Switch B(Problematic)
Mgmt IP Addresses:
Router 10.100.25.3
Switch A: 10.100.25.1
Switch B:10.100.25.2
Switch A learns mac-address via vlan 1 as its considereing interface in vlan 1.
configuration of Switch B(Problematic):
interface GigabitEthernet0/48
switchport trunk encapsulation dot1q
switchport mode trunk
switchport nonegotiate
interface Vlan10
ip address 10.100.25.2 255.255.255.0
configuration on Switch A:
interface Vlan10
ip address 10.100.25.1 255.255.255.0
ip helper-address 10.100.4.4
interface GigabitEthernet1/0/48
switchport mode trunk
switchport nonegotiate
08-31-2015 04:48 AM
Please add the "show vlan" on switch B
08-31-2015 04:50 AM
I don't have access to switch B.
08-31-2015 04:52 AM
it's look like you got some kind of configuration problem there, you will have to get console access to solve it.
08-31-2015 07:05 AM
when I run command "sh cdp nei" I can see neighbor connected but when I run "sh cdp nei detail" I don't see neighbor detail there.
Shahzad
08-31-2015 08:14 AM
From your show cdp neighbor detail output:
Device ID: CISCO3560X
Entry address(es):
IP address: 10.100.25.3
Platform: cisco WS-C3560X-48P, Capabilities: Switch IGMP
Interface: GigabitEthernet1/0/48, Port ID (outgoing port): GigabitEthernet0/48
Holdtime : 127 sec
09-03-2015 01:03 AM
I checked through console, 10.100.25.3 was assigned to vlan10 on switch B, which is mgmt. IP of router. I can't believe how it was happened.
Shahzad
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