My Network Lab: July 2026

Here's a Cisco link to renumber a Cisco switch stack. Validate the current switch stack number using the show switch command. In my scenario, it's only a single switch which was pulled out from a previous switch stack. I had to renumber the switch using the privilege command switch <current-number> renumber <new-number> in order to display the correct interface number. A reload is required afterwards.

C9300#switch ?
<1-16> Switch Number
clear Reset the switch mode to N+1

C9300#switch 2 ?
priority Set the priority of the specified switch
renumber Renumber the specified switch number
ring-speed Set the switch ring speed to low/high
role Set the new switch mode of the Switch
stack Stack port enable or disable

C9300#switch 2 renumber ?
<1-16> New number of the Switch

C9300#switch 2 renumber 1
WARNING: Changing the switch number may result in a configuration change for that switch. The interface configuration associated with the old switch number will remain as a provisioned configuration. New Switch Number will be effective after next reboot. Do you want to continue?[y/n]? [yes]: yes

C9300#reload

System configuration has been modified. Save? [yes/no]: y
Building configuration...
[OK]Reload command is being issued on Active unit, this will reload the whole stack

The switch was already in the correct number/order but it still had Gi2/0/x interfaces.

C9300#show switch
Switch/Stack Mac Address : 2416.9d7b.1234 - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
-------------------------------------------------------------------------------------
*1 Active 2416.9d7b.1234 1 V03 Ready
2 Member 0000.0000.0000 0 Provisioned

C9300#show interface description
Interface Status Protocol Description
Vl1 up up
Gi0/0 admin down down
Gi1/0/1 down down
Gi1/0/2 down down
Gi1/0/3 down down
Gi1/0/4 down down
Gi1/0/5 down down
Gi1/0/6 down down
Gi1/0/7 down down
Gi1/0/8 down down
Gi1/0/9 down down
Gi1/0/10 down down
Gi1/0/11 down down
Gi1/0/12 down down
Gi1/0/13 down down
Gi1/0/14 down down
Gi1/0/15 down down
Gi1/0/16 down down
Gi1/0/17 down down
Gi1/0/18 down down
Gi1/0/19 down down
Gi1/0/20 down down
Gi1/0/21 down down
Gi1/0/22 down down
Gi1/0/23 down down
Gi1/0/24 down down
Gi1/0/25 down down
Gi1/0/26 down down
Gi1/0/27 down down
Gi1/0/28 down down
Gi1/0/29 down down
Gi1/0/30 down down
Gi1/0/31 down down
Gi1/0/32 down down
Gi1/0/33 down down
Gi1/0/34 down down
Gi1/0/35 down down
Gi1/0/36 down down
Gi1/0/37 down down
Gi1/0/38 down down
Gi1/0/39 down down
Gi1/0/40 down down
Gi1/0/41 down down
Gi1/0/42 down down
Gi1/0/43 down down
Gi1/0/44 down down
Gi1/0/45 down down
Gi1/0/46 down down
Gi1/0/47 down down
Gi1/0/48 down down
Gi1/1/1 down down
Gi1/1/2 down down
Gi1/1/3 down down
Gi1/1/4 down down
Te1/1/1 down down
Te1/1/2 down down
Te1/1/3 down down
Te1/1/4 down down
Te1/1/5 down down
Te1/1/6 down down
Te1/1/7 down down
Te1/1/8 down down
Fo1/1/1 down down
Fo1/1/2 down down
Twe1/1/1 down down
Twe1/1/2 down down
Ap1/0/1 up up
Gi2/0/1 down down
Gi2/0/2 down down
Gi2/0/3 down down
Gi2/0/4 down down
Gi2/0/5 down down
Gi2/0/6 down down
Gi2/0/7 down down
Gi2/0/8 down down
Gi2/0/9 down down
Gi2/0/10 down down
Gi2/0/11 down down
Gi2/0/12 down down
Gi2/0/13 down down
Gi2/0/14 down down
Gi2/0/15 down down
Gi2/0/16 down down
Gi2/0/17 down down
Gi2/0/18 down down
Gi2/0/19 down down
Gi2/0/20 down down
Gi2/0/21 down down
Gi2/0/22 down down
Gi2/0/23 down down
Gi2/0/24 down down
Gi2/0/25 down down
Gi2/0/26 down down
Gi2/0/27 down down
Gi2/0/28 down down
Gi2/0/29 down down
Gi2/0/30 down down
Gi2/0/31 down down
Gi2/0/32 down down
Gi2/0/33 down down
Gi2/0/34 down down
Gi2/0/35 down down
Gi2/0/36 down down
Gi2/0/37 down down
Gi2/0/38 down down
Gi2/0/39 down down
Gi2/0/40 down down
Gi2/0/41 down down
Gi2/0/42 down down
Gi2/0/43 down down
Gi2/0/44 down down
Gi2/0/45 down down
Gi2/0/46 down down
Gi2/0/47 down down
Gi2/0/48 down down
Gi2/1/1 down down
Gi2/1/2 down down
Gi2/1/3 down down
Gi2/1/4 down down
Te2/1/1 down down
Te2/1/2 down down
Te2/1/3 down down
Te2/1/4 down down
Te2/1/5 down down
Te2/1/6 down down
Te2/1/7 down down
Te2/1/8 down down
Fo2/1/1 down down
Fo2/1/2 down down
Twe2/1/1 down down
Twe2/1/2 down down
Ap2/0/1 down down

It still had the switch <number> provision <platform> command, which is used to preconfigure interfaces before physically stacking the switch. I just negate using switch 2 provision c9300-48p to remove the Gi2/0/x interfaces. You'll need to reload to take effect.

C9300#show run | i switch
switch 1 provision c9300-48p
switch 2 provision c9300-48p
C9300#
C9300#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
C9300(config)#no switch 2 provision c9300-48p
C9300(config)#end
C9300#write memory
Building configuration...
[OK]
C9300#reload
Reload command is being issued on Active unit, this will reload the whole stack
Proceed with reload? [confirm]

I wasn't able to remotely SSH to a Cisco router using different management jump servers. I got different error message below.

admin@server01:~$ ssh 172.27.6.1

The authenticity of host '172.27.6.1 (172.27.6.1)' can't be established.

RSA key fingerprint is SHA256:ESsfNyzjhVIYlQ/ZWDwGBeBJg6Hn1mfSO3NEW012345.

This key is not known by any other names.

Are you sure you want to continue connecting (yes/no/[fingerprint])? yes

Warning: Permanently added '172.27.6.1' (RSA) to the list of known hosts.

ssh_dispatch_run_fatal: Connection to 172.27.6.1 port 22: incorrect signature

admin@server02~$ ssh 172.27.6.1

The authenticity of host '172.27.6.1 (172.27.6.1)' can't be established.

RSA key fingerprint is 43:03:59:93:b3:98:46:92:64:bd:8d:f7:2d:12:34:56.

Are you sure you want to continue connecting (yes/no)? yes

Warning: Permanently added '172.27.6.1' (RSA) to the list of known hosts.

RSA_public_decrypt failed: error:0407006A:rsa routines:RSA_padding_check_PKCS1_type_1:block type is not 01

key_verify failed for server_host_key

I've temporary enabled Telnet and regenerated (zeroise) the SSH/RSA key. Make sure domain name is configured.

Router#show ip ssh

SSH Enabled - version 1.99

Authentication methods:publickey,keyboard-interactive,password

Authentication Publickey Algorithms:x509v3-ssh-rsa,ssh-rsa

Hostkey Algorithms:x509v3-ssh-rsa,ssh-rsa

Encryption Algorithms:aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc

MAC Algorithms:hmac-sha1,hmac-sha1-96

Authentication timeout: 120 secs; Authentication retries: 3

Minimum expected Diffie Hellman key size : 1024 bits

IOS Keys in SECSH format(ssh-rsa, base64 encoded): CISCO_IDEVID_SUDI

ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDGzzxJCzuFj/sHvJuZA4fzhV6t6XHDR73aCPNZZxoD

5iuUp8pu14OAV5L+Zu+EL6QZqV88bcmRvSYp05JmLrGmlBv4QAJluyla85PnZurC4OBxSxWg/gx40mzJ

yWeHnlQd1euxbo0J0+gkwLQYWmrsgGLpfqhXKDAUVCzhPdpjRdUT3wg2Cbk49YSr+LntrPwBVBRF7dEl

p1mGs2ykL0LDmU6rlWf9O1aRsUYmFhgK16pFekFGluKmrdaoak5sfk9ch38rr5O8rejcsjp408PyeJrS

jgB3sVTBpywcG39LtmLaku5xQrGfjlowyBOyRaLRgbjZDvdfl7aqABC12345

Router#show run | inc domain

no ip domain lookup

ip domain name local.com

I initially removed the SSH/RSA key and configured the basic rsa key without configuring a label but still couldn't SSH.

Router(config)#crypto key zeroize

% All keys will be removed.

% All router certs issued using these keys will also be removed.

Do you really want to remove these keys? [yes/no]: yes

Router(config)#crypto key generate rsa modulus 2048

The name for the keys will be: Router.local.com

% The key modulus size is 2048 bits

% Generating 2048 bit RSA keys, keys will be non-exportable...

[OK] (elapsed time was 0 seconds)

I've zerioise the SSH key again and explicitly configured a label and keypair-name. I was able to SSH to the router afterwards.

Router(config)#crypto key zeroize

% All keys will be removed.

% All router certs issued using these keys will also be removed.

Do you really want to remove these keys? [yes/no]: yes

Router(config)#

Router(config)#crypto key generate rsa mod 2048 label Router.local.com

The name for the keys will be: Router.local.com

% The key modulus size is 2048 bits

% Generating 2048 bit RSA keys, keys will be non-exportable...

[OK] (elapsed time was 2 seconds)

Router(config)#ip ssh rsa keypair-name Router.local.com

Router(config)# end

Router#write memory

Building configuration...

[OK]

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