I have these switchs :
2 x 9300 : already configured by a other person
4 x 2960-x : new, out of the box
I configure IP, VLAN,Trunk,ports, ..., etc... for the 2960-x
And it"s OK.
Then, I connect one the 2960-x with the 9300, on the same configuration trunk port .
But, no ping.
(I already open a other issue for that)
Then, I see on the 9300, that the default VLAN (native) was not 1 but a other value, on the entire switch for all the ports.
Then, I decide to change on the 2960-x this kind of value "native vlan" with the same new value.
And just after that, all my switchs 2960-x can't be connected between them; no ping, nothing !
A big mess !
Then, I reset this evening all of them (2960-x), to reconfigure them later.
I would like to understand why this kind of change (value from 1 to X for "native vlan) can crash the network ?
Please show us:
show Ip int br
show int trunk
from 2960 and 9300
I read it; and I have the feeling that it's NOT recommandend to change the value of the "native vlan" from 1 to X on a TRUNK port.
It's mandatory to use the value 1.
Is it correct ?
No, in specific case, vlan1 may be not native. But in common case, yes, native vlan may be 1.
in Your case, what VLAN You use I will can tell anything after view config (VLAN’s and interfaces)
Vlan 1 is the default native vlan that comes with all switches. If you want to keep the native vlan as vlan 1, there is no need for any configuration. If you want to configure a different vlan as native vlan (say 50), than you need to configure it on all switches including the trunk ports.
Then apply the New value for "native vlan" on all the network port interfaces for all the switchs ?
Int all (instead gi/...)
Switchport trunk native vlan 50
Do wr mem
Is it correct ?
I would suggest the start from Core to all devices as @Reza Sharifi suggested this required all switches.
create VLAN 50 on all the switched and amend the config as you described.
As i have seen some Cat 9300 if the native VLAN Mismatches/VLAN not available in the database - the Port-channel go down. so make sure you have enough access to the device before changing anything.
On the 9300, the "native vlan" is 50.
And, I just update the trunk port and add this "native vlan" 50 to the trunk on the 9300 (port 24) and on the 2960-X (port 24); and just after that, all the ping don't work.
Isi it something like that ?
But inside the web page of the 9300, I can see the link with 2960-X.
Then, I need to change the "native vlan" value from 1 to 50, on all the network ports before change it on the TRUNK port, for the 2 switchs (2960-X and 9300).
What are the commands ?
int all (is it correct ?) or int Gi/1-Gi/23
(because do "int Gi/1", "int Gi/2", ...for each port is a long way)
switchport native vlan 50 (Is it correct ?)
do wr mem
No, If You wnt to configure multiple ports You must use:
Int range gig0/1-24
Example for configure ports from Gig0/1 to Gig0/24
Also access port must be configured like:
switchport mode access
switchport access vlan 50
And may be You have phones and separate VLAN for it then
swichport voice vlan XX
FYI - Native vlan ISNT switch specific, its port specific, meaning you can have multiple native vlans on various switch trunk interconnects on the same switch, only the two sides of each trunk need to have the same native vlan ID.
Can you post the full configuration look? for all the switches.
do you also have command other than native vlan allowed VLAN List in the port-channel like below on the port-channel connected to parent switch?
Note : this command not required to add to the Access ports, i saw you have added this command to all the interfaces.
the command for native VLAN as below example only :
interface port-channel 1
switchport trunk native vlan 50
switchport trunk allowed vlan 50, 60,70 ...So on
Access port config should remain as same as access port the port belong to which VLAN
interface g 1/1
switchport mode access
switchport access vlan 60