Solved: Re: 2960-S 24p switch not keeping config

pedroalvesbatista · ‎04-12-2022

Hi fellows,

I'm using a 2960-S switch on my test lab, for learning purposes, and when trying to ping between hosts and VLANs, I'm getting some troubles. After some troubleshooting with a buddy of mine, we discovered that this might be due to NVRAM not being able to keep configurations over ports. I can see VLANs, and their respective configurations as well, but when it comes to my trunk port in g0/1, I can that this port is not holding any configuration I've made.

Searching around, I found that perhaps configuration register is putting me into this issue, as for some switches and routers, the default is 0xF. I also found some tricks to change it from 0xF to 0x2142 or 0x2102. Is this true ? Changing this would have any effect in my switch ?

I'm even thinking that maybe is time to get rid of this switch and try to get another one, but for the prices I'm able to afford, 3560 series switch is the only viable, but, the configs set is almost the same as of 2960 when it comes to configuration register.

Richard Burts · ‎04-18-2022

Thanks for the update. It is good to have the complete running config. I do have a few comments based on the config:

- you have configured both enable password and enable secret. When enable secret is configured then enable password is ignored. Since it is not being used I suggest that you remove it from the config.

- you have vlan 10 and a vlan 10 interface (with an IP). So vlan 10 should work (assuming that there are devices connected to the interfaces in that vlan).

- you have vlan 20 configured with a couple of ports in it. the vlan should work if there are devices connected to the ports in that vlan. But there is no vlan interface for vlan 20.

- you have vlan 30 interface but as far as I can tell there is no vlan 30.

- the configured default-gateway is an address in vlan 30. What is that? Where is that? In the current configuration this will not work.

- it appears that ip routing is not enabled. So the switch is not doing any routing between vlans.

- there is a trunk configured on the first interface. What does the trunk connect to?

- assuming that the trunk connects to a router, does the router have vlan subinterfaces configured for vlans 10 and 20?

Based on what I see in the configuration I would expect that any device in vlan 10 should communicate successfully with any other device in vlan 10. I would expect that any device in vlan 20 should communicate successfully with any other device in vlan 20. Whether devices in vlan 10 and 20 can communicate with each other depends on how the router is configured.

I am still confused about whether the configuration is stable or whether you still believe that parts of the config are not maintained. Any clarification about that would be appreciated.

If things still are not working then I would ask for the following things:

- output of show interface status on the switch

- output of show cdp neighbor on the router

- output of show run on the router

- output of slow ip route on the router

- output of show arp on the router

- description of what is not working

HTH

Rick

View solution in original post

Leo Laohoo · ‎04-12-2022

Post the complete output to the following commands:

sh version
sh boot
dir

pedroalvesbatista · ‎04-14-2022

mylabswitch#sh ver
Cisco IOS Software, C2960S Software (C2960S-UNIVERSALK9-M), Version 12.2(58)SE1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2011 by Cisco Systems, Inc.
Compiled Thu 05-May-11 03:03 by prod_rel_team

ROM: Bootstrap program is Alpha board boot loader
BOOTLDR: C2960S Boot Loader (C2960S-HBOOT-M) Version 12.2(53r)SE, RELEASE SOFTW)

mylabswitch uptime is 2 days, 0 minutes
System returned to ROM by power-on                                              
System image file is "flash:c2960s-universalk9-mz.122-58.SE1.bin"

mylabswitch#sh boot            
BOOT path-list : flash:c2960s-universalk9-mz.122-58.SE1.bin 
Config file : flash:/config.text 
Private Config file : flash:/private-config.text 
Enable Break : no 
Manual Boot : no 
HELPER path-list : 
Auto upgrade : yes 
Auto upgrade path : 
NVRAM/Config file 
buffer size: 524288 
Timeout for Config 
Download: 0 seconds 
Config Download 
via DHCP: disabled (next boot: disabled)

mylabswitch#dir
Directory of flash:/ 

2 -rwx 13245186 Mar 1 1993 00:03:29 +00:00 c2960s-universalk9-mz.122n
3 -rwx 426 Mar 1 1993 00:06:18 +00:00 express_setup.debug 
4 -rwx 736 Mar 2 1993 01:19:06 +00:00 vlan.dat 
5 -rwx 18629690 Mar 15 1993 00:30:04 +00:00 c3560e-universalk9-mz.150n
6 -rwx 856 Mar 1 1993 00:00:43 +00:00 vlan.dat.renamed 
7 -rwx 1913 Mar 1 1993 00:00:58 +00:00 private-config.text 
8 -rwx 3975 Mar 1 1993 00:00:58 +00:00 config.text 
9 -rwx 1913 Mar 1 1993 00:01:00 +00:00 private-config.text.renamd
10 -rwx 3096 Mar 1 1993 00:00:58 +00:00 multiple-fs 
11 -rwx 1861 Mar 1 1993 00:01:00 +00:00 config.text.renamed 

57931776 bytes total (25776640 bytes free)

Leo Laohoo · ‎04-14-2022

Inspect the "Mode" button. Is it jammed?

Richard Burts · ‎04-17-2022

Both the show version output and the show run output are truncated. They show only the first page. Information that we need is on the following pages. Can you find a way to post more complete outputs?

HTH

Rick

Leo Laohoo · ‎04-17-2022

¯\_(ツ)_/¯

It is either the person is very "secretive" or he does not know how to "cut-n-paste" properly.

Either way, until I see the output I've requested I cannot provide any useful troubleshooting.

pedroalvesbatista · ‎04-17-2022

Hi Leo,

Yeah, probably I did miss something along the way.

Leo Laohoo · ‎04-17-2022

Every terminal application has the ability to log the output to a text file.

Try it.

pedroalvesbatista · ‎04-17-2022

The output is exactly the same as I wrote before.

Richard Burts · ‎04-17-2022

I do not know how you are getting this output. But the output that you post for show version is the first page of a multi page output. The thing that we are most interested in is the config register value with is about the last item in the complete output.

Similarly the output of show run is the first page of a many page output. Is it possible that when you issue the show commands that at the bottom of the first page there is a prompt that says "more"? If so then press return to see the next page(s).

Without the complete output we are not able to understand your issue or to give you good advice.

HTH

Rick

Richard Burts · ‎04-17-2022

In the original post you mention the config register and ask if changing it could impact your switch. The answer is that changing the value of the config register could indeed impact your switch. Especially changing it to 0x2142 would cause the switch to not use the startup config when it reboots and result in losing the config.

Many discussions mention 0x2102 as the default value. And that is generally true for IOS routers. It is frequently not true for switches. As you mention the default for this switch is 0xf. While we attempt to solve the issue about how to get complete output for the show commands, I suggest that you explicitly set the config register to 0xf and see if the behavior changes.

HTH

Rick

Richard Burts · ‎04-18-2022

In reading through the discussion again I wonder if we are correctly understanding the issue. Especially based on the title of the post being about switch not keeping config I (and I believe several of my colleagues) have assumed that the issue was that the switch was losing all of your config changes. And the most likely cause of this would be the config register. But in reading the original post again I notice that you really focused on the configuration of a specific interface as a trunk. Can you clarify whether the issue is the more general one that the switch loses all of your configuration changes or is the more specific that this particular interface does not keep config changes?

HTH

Rick

pedroalvesbatista · ‎04-18-2022

Hi Rick,

The main issue I'm facing right now, is that, for what me and a friend of mine who was helping me to debug this, I can't reach from one host to another in the same VLAN. We guessed that perhaps the problem was that trunk interface might not be performing so well to allow traffic to go in and out. That's why I mentioned the configuration register, because I did some research about what could be causing my VLANs to not allow traffic.

pedroalvesbatista · ‎04-18-2022

In some researches, folks were suggesting to use the Mode button to go to default mode, and then go that way. But some folks also told that this switch model is not affordable to change configuration register, what I don't know for sure if is completely true.

pedroalvesbatista · ‎04-18-2022

Alright Rick,

Here follows the complete output :

Building configuration...

Current configuration : 5396 bytes
!
! Last configuration change at 01:09:13 UTC Wed Mar 3 1993
!
version 12.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname mylabswitch                                                        
!                                                                               
boot-start-marker                                                               
boot-end-marker                                                                 
!                                                                               
!                                                                               
enable secret 5 $1$9DTB$MEpuhl5mrBW.5HO7jVKYk.                                  
enable password mylabswitch#enable0                                            
!                                                                               
no aaa new-model                                                                
!                                                                               
!                                                                               
!                                                                               
!                                                                               
no setup express                                                                
!                                                                               
crypto pki trustpoint TP-self-signed-1888268160                                 
 enrollment selfsigned                                                          
 subject-name cn=IOS-Self-Signed-Certificate-1888268160                         
 revocation-check none                                                          
 rsakeypair TP-self-signed-1888268160                                           
!                                                                               
!                                                                               
crypto pki certificate chain TP-self-signed-1888268160                          
 certificate self-signed 01                                                     
  30820247 308201B0 A0030201 02020101 300D0609 2A864886 F70D0101 04050030       
  31312F30 2D060355 04031326 494F532D 53656C66 2D536967 6E65642D 43657274       
  69666963 6174652D 31383838 32363831 3630301E 170D3933 30333031 30303030       
  35365A17 0D323030 31303130 30303030 305A3031 312F302D 06035504 03132649       
  4F532D53 656C662D 5369676E 65642D43 65727469 66696361 74652D31 38383832       
  36383136 3030819F 300D0609 2A864886 F70D0101 01050003 818D0030 81890281       
  8100C554 66CCBC80 AEE83C49 778E901C F8E4CFE3 B7FACF31 87F8480A 5105C08A       
  160DA634 09004ED7 F98579BB 376DDFDC 710608AE DD14F5D5 756DDE90 7D5847E1       
  E713FAFC 9AEC4F1D B8E29E69 5D4A6167 3ECF6287 C975802F A8D32CC6 5A342551       
  6E367F01 C58AF2BB 87FC0524 C22CD49B 2C640816 54DD21F0 16182165 FC98363E       
  27F70203 010001A3 6F306D30 0F060355 1D130101 FF040530 030101FF 301A0603       
  551D1104 13301182 0F6B7572 696C6F6E 67617377 69746368 301F0603 551D2304       
  18301680 14AD7584 0C86BDE2 1DAE926B 0DB7EB68 F032A7F7 B1301D06 03551D0E       
  04160414 AD75840C 86BDE21D AE926B0D B7EB68F0 32A7F7B1 300D0609 2A864886       
  F70D0101 04050003 8181001C CAAE92D1 1FC9B320 A0BF7F66 FB8ECBD2 59ABA537       
  DA73E52B 7496FC6F 46345CF9 A7E8881E 4F877C5E B00F141A 3BA21354 7A9C9EC6       
  AAD53993 CD406B3A B571C02D BA874A3B 86BCCE83 9CF058F4 FF507755 456C6495       
  5AF7D180 5A5A8053 008B98D8 CB96A891 F2745012 B2C13A4F B625C49C 0A0F8071       
  19D18106 815BB180 634DE3                                                      
        quit                                                                    
spanning-tree mode pvst                                                         
spanning-tree extend system-id                                                  
!                                                                               
!                                                                               
!                                                                               
!                                                                               
vlan internal allocation policy ascending                                       
!                                                                               
!                                                                               
!                                                                               
!                                                                               
!                                                                               
!                                                                               
interface FastEthernet0                                                         
 no ip address                                                                  
 shutdown                                                                       
!                                                                               
interface GigabitEthernet0/1                                                    
 description RT-2901-G0/1                                                       
 switchport trunk native vlan 1001                                              
 switchport trunk allowed vlan 10,20,30                                         
 switchport mode trunk                                                          
!                                                                               
interface GigabitEthernet0/2                                                    
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/3                                                    
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/4                                                    
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/5                                                    
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/6                                                    
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/7                                                    
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/8                                                    
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/9                                                    
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/10                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/11                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/12                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/13                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/14                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/15                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/16                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/17                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/18                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/19                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/20                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/21                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/22                                                   
 description Kurilonga-SRV                                                      
 switchport access vlan 10                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/23                                                   
 description Menga-SRV                                                          
 switchport access vlan 20                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/24                                                   
 description Menga-SRV                                                          
 switchport access vlan 20                                                      
 switchport mode access                                                         
!                                                                               
interface GigabitEthernet0/25                                                   
!                                                                               
interface GigabitEthernet0/26                                                   
 description SFP-PORT                                                           
!                                                                               
interface Vlan1                                                                 
 no ip address                                                                  
 shutdown                                                                       
!                                                                               
interface Vlan10                                                                
 ip address 192.168.10.2 255.255.255.0                                          
!                                                                               
interface Vlan30                                                                
 ip address 192.168.30.2 255.255.255.0                                          
!                                                                               
ip default-gateway 192.168.30.1                                                 
ip http server                                                                  
ip http secure-server                                                           
!                                                                               
logging esm config                                                              
snmp-server community public RO                                                 
!                                                                               
line con 0                                                                      
 exec-timeout 0 0                                                               
line vty 0 4                                                                    
 password mylabswitch#2022                                                    
 login                                                                          
line vty 5 15                                                                   
 password mylabswitch#2022                                                     
 login                                                                          
!                                                                               
end