Welcome back everyone. I am not going to bore you to death with this one VLAN trunk configuration. Okay, configuring trunking on your switches, you got it. You go to your layer two, switch port mode trunk. Then you go inside whatever interface is facing a switch, or it's facing a router or a normal layer three device, boom switch port mode trunk. If it's a layer three switch, you go switch port trunk encapsulation because it gives you the option of ISIL and Dhawan Q.
All right. All the commands you should know. And these are optional memory I told you, you want to change the native VLAN so he goes to his port trunk native VLAN 200. Okay, careful. Don't get a native VLAN mismatch. So if you chose you know, one, you better change them all.
Switches Port trunk allowed VLANs that allowed the trouble of VLANs you want to allow across a strong Port 200 to 220 and switch port mode dynamic, desirable, meaning it's going to be automatically going to detect automatically what they are. Now, listen, be careful with this allowed command. Just like when doing GPOs right and servers, you can get into a web of everything while allowing this VLAN but not that VLAN put this VLAN then if you have no documentation, you have no idea what your online or permitting deny, you know, so be very careful when knowing this guy right here. This is something as recommended that you do change your native VLANs as we all know, the native VLAN is one you should change all your native VLAN once you change the native VLAN you got to take all those ports and put them on the native VLAN Okay, so you got to assign the ports to the native VLAN leaving the default VLAN VLAN one empty Okay, but just be careful because you got to do it on all switches or you're gonna have a native VLAN mismatch.
And when you send a frame, it may just decide to go different places. So be very careful. Now. Lastly, some show commands show interface trunk, it shows you a port the trunk, or you do show interface f 00, F Zero 22 switch port, and then say hey, I want to go to that port. I don't know all the details, all the all that switch port of that particular port, as you can tell this is access motive as trunking modes and give a bunch of information. Again, we'll see it in the lab.
All right, are you going to simply do a show run a show start and take a look at which ports are trunk and go just go down the road? Okay, well, these are three commands. These you know again, no biggie. Careful when changing the veena you're changing a wall and be careful with what you're allowing if you're allowing it not allowing it. If you are changing native you know, make sure you're changing them all because you could get errors. So pay attention because if you got hundreds or thousands switches.
That could be a problem that could be a fall in the next