Default Gateway on vlan interface

[ejdrijin1]

Hi,

I want to set a default gateway on a layer 3 switch for VLAN 100.

If I give an IP for interface VLAN 100 does it work or do I need to set it on an actual interface (port - example: int g1/0/1)?

Thanks

[Seb Rupik]

Hi there,

Creating a Layer3 interface (int vlan100) would create an SVI for that VLAN. Applying an IP address to that SVI would provide a default gateway for the VLAN/ subnet. You would make this SVI available by using switchports in access or trunk mode.

Applying an IP address to a interface would create a routed interface.

cheers,

Seb.

[ejdrijin1]

Hi Seb,

Thanks for your reply. So if I want to do routing to this subnet/vlan I need to do it on the interface, right?

Thanks.

[Seb Rupik]

Depends on the device.

Routers typically only support routed interfaces, whereas Layer3 switches support both routed interfaces and also SVIs.

What hardware are you using?

cheers,

Seb.

[ejdrijin1]

Thanks for your reply.

I am using Cisco 3750X.

[Seb Rupik]

A layer3 switch. In which case, follow the configuration which @Deepak Kumar mentioned in his post below.

Likewise as @Joseph W. Doherty noted, you will also need a way to route traffic to other subnets/ the internet.

cheers,

Seb.

[Deepak Kumar]

Hi, 

You didn't write the error message and switch model number. 

I hope your configuration as below

Vlan 100

exit

!

interface vlan 100

ip add 192.168.1.1 255.255.255.0  !----> Example only, you can use available subnet.

no shut

!

!

interface gig1/0/1

switchport mode access

switchport access vlan 100

spanningtree portfast 

no shut

!

!

Now configure the IP address in the system which is connected to Gi1/0/1 

IP address: 192.168.1.100 / 255.255.255.0

default Gateway: 192.168.1.1

Now ping to the default gateway and share the output. 

Regards,

Deepak Kumar

[Joseph W. Doherty]

"I want to set a default gateway on a layer 3 switch for VLAN 100."

Unclear what you want to accomplish. Do you want a L3 switch to host a gateway for VLAN 100, and also insure it's the default gateway for hosts on VLAN 100 or are you trying to have VLAN 100, on the switch, have a default gateway?

[ejdrijin1]

I want to create a new subnet 192.168.1.0/24 and set 192.168.1.1 as the default gateway of the VLAN.

My question is does the 192.168.1.1 need to be set on the int VLAN 100 or the g1/0/1?

Thanks.

[Deepak Kumar]

Hi,

It will under the VLAN 100.

Regards,

Deepak Kumar

[Joseph W. Doherty]

It might be done either way - which depends on what your topology is.

Assuming VLAN 100 is also defined on your 3750X, you would define a SVI for VLAN 100 and define the IP there. However, if what was attached to g1/0/1 was another switch, and VLAN 100 was only hosted on it, you could define the IP on g1/0/1, after making the port a non-switchport.

BTW, doing either, alone, isn't what defines a default gateway; it's generally up to your clients to decide what IP they will use for gateway.