Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

vlans error

i created to vlans, and belongs ports, and connect computers. and then i put:

int vlan 2

no shut

i get massage: vlan 2 is up, vlan 3 is down.

then i put: int vlan 3, no shut

and i get: vlan 3 is up, vlan 2 is down.

i can't turn on 2 vlans at the same time, what's wrong?


Cisco Employee

Re: vlans error

Hi Amir,

I believe you have 2950 switch which is a pure layer 2 switch and the vlans which you are creating a layer 3 logical interface so layer 2 switch only support one active layer 3 interface at a time for management purpose and taht si the reason when you no shut second interface first one will go down.

What you need to do is either go to vlan database mode and create layer 2 vlans or you can do it from global config mode

Something like this

switch(config)#vlan 2


switch(config)#vlan 3


switch(config)#wr mem



*Pls rate all helpfull post

New Member

Re: vlans error

you right.

i really have a 2950 SW,

but what is the difference between layer 2/3 vlans?

i need 2 vlans that will go trough the trunk to the FW and then routed to their places.

does it work?

and what about address to vlans? in other words, which command / configuration i need except the vlan 1, exit. vlan 2, exit.

? thanks

Re: vlans error


Let us know which switch you have.

On a layer 2 box you cannot have 2 SVI's up at the same time. We use SVI on alayer 2 box just for the management part and it doesnot do any routing so that's why only 1 SVI is up at one time.


-amit singh

New Member

Re: vlans error

it's 2950 series sw.

is there software upgrade that can support real work vlans on that SW?

Re: vlans error


No it is not possible as u r 2950 is a pure layer 2 switch which can have the funtionality of layer 3 even if u upgrade the software.



New Member

Re: vlans error

OK i got it, so now i need another solution

I have a core 2950 SW that connected to a checkpoint FW, and a 2 cisco 2950 SWitces

i want to different networks,

so i connect 1st sw to the core, and the 2nd to the core to (without connecting the 2 new together, 1st will be 192.168.1.x and 2nd will be 192.168.2.x) and i will connect 1 port in the core SW to a dmz NIC in the cp fw. 192.168.2.x

and the existing port connected to the lan nic in 192.168.1.x

it's now so securly but less broadcast i think i have.

anyway, does it work?

and if u have something to add/modify

please tell me

New Member

Re: vlans error

i ask the customer

and he told me that the core sw is 2950 series and it has work vlans on it allready, so i checked and i saw that the core sw is Enhanced ImageWS-C2950G-24 EI

and the new SWitches are WS-C2950sx-24 Standard image only

does it make the differnce?

* does the diffrence is only at the image or at the hardware to?

Re: vlans error

The difference is only in the image and featuresets Like ehanced security, QOS and acl's.

2950 Swithes with Enhanced image

2950 Switches with Standard image


-amit singh

CreatePlease to create content