Cisco Trunking vlan tagging

Ronnie Wong

So on a switch you can creat a virtual interface called interface vlan 1 and assign an ip address to it.

SW1(config)#interface vlan 16
SW1(config-if)#ip address 192.168.16.1 255.255.255.0
SW1(config-if)#no shutdown

If I have a switchport in vlan 16 and a host is attached to the device on that port. You can assign a static ip address to it e.g. 192.168.16.100 255.255.255.0 default gateway: 192.168.16.1

you should be able to ping 192.168.16.1 sucessfully.

Ronnie Wong

@Victor-Rosa-Serrano,

The problem that you'll have is that you'll need a separate gateway for vlans 10, 20 and 50. You will not share a gateway for 10, 20 and 50.

Then you'll have to configure reachability with a port going to each gateway or you can configure a trunk...and have that trunk connect to a ROUTER that will allow you to configure subinterfaces on that port as your gateways.

Victor Rosa-Serrano

So I create the trunk, So I need to create the sub interfaces in the router then, That may be the part that I'm missing. Now what you mentioned earlier make sense that my soho may not support multiple scopes. I'll try again with a manage Sophos firewall and will update.

Victor Rosa-Serrano

Victor Rosa-Serrano

So I have a workstation in vlan 10 but no dhcp. But the trunk should allow that traffic to my home router. Everything seems ok in that side righ?

Ronnie Wong

@Victor-Rosa-Serrano,

Plug your SOHO router that is serving dhcp into fa4/0/10, fa4/0/11, fa4/0/12, fa4/0/20

If your router will not allow you to create scopes for vlan 10 and vlan 20. Then it will only serve one vlan.

Victor Rosa-Serrano

I did What you said and instead I have an image from a sophos router. It worked, But Now I would like to know, How to add the remain vlans to work, like vlan20. Should I create a relay agent for dhcp? Thanks

Ronnie Wong

@Victor-Rosa-Serrano,

Does your DHCP router support multiple scopes? if not, you will need to put a DHCP in each VLAN.

Victor Rosa-Serrano

No it doesn't but I could place a dchp server. In the real world they don't place relay agents? How will that be configure. If My dhcp is in vlan 10 I know I could create a relay agent to comunicate with it. Thanks for all your help Mr Ronnie

Ronnie Wong

@Victor-Rosa-Serrano,

You will find dhcp-relays in the real world to allow you to send the DHCP Broadcast beyond the Broadcast Domain.
I'm sure that within our Cisco courses you'll see how to configure a DHCP relay agent.

I've never tried to do this the way you're describing.

You'll need a need either a router between the vlans or setup SVIs, then configure the dhcp relay agent correctly.