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Trouble with additional VLAN

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Trouble with additional VLAN

I closed a previous thread thinking I had things resolved... Now I'm back to the drawing board and trying to keep things simple.

I have a Sonicwall Pro 2040 enhanced that is my gateway to the internet. Inside, the net is, and spans across six IDFs. Behind the Sonicwall I have a 2900-24, 2900-48, and several 1800-24's.

My goal is to get each IDF on it's own VLAN.

Presently I have static routes added to the Sonicwall to direct VLAN traffic to the 2900-24., .2.0/24, .3.0/24, etc., all point back to (2900-24). The idea was that until I can get everything looking at the switch, at least the traffic isn't dropped...

So with the config below, VLAN 11 works. I have a test port configured as untagged, and when I connect to that port my DHCP server gives me a correct address and I can talk to the GW address for that VLAN, the main switch, the firewall, and hosts inbetween. I can also ping the second VLAN gateway. If I connect to the other test port untagged VLAN 12, I get an IP from the VLAN 11 subnet and can't talk to anything.

It's almost as if my DHCP server, once assigning an address to a VLAN'd PC, can't determine there are additional VLANs in place.

Ideally, the 2900-24 will feed four IDF's, and the 2900-48 will feed the last two. They are not stacked, but do have the two 10Gb connections trunked.

I'm not sure where to look. I've been through these forms and searched the documentation, which has lead me to make a variety of changes to the config both via the CLI and web interfaces (some are CLI only)...

Any help / suggestions would be appreciated. Thanks!

Running configuration:

; J9049A Configuration Editor; Created on release #T.13.23

hostname "MDF-2900-24G"
snmp-server location "MDF-LB-2nd-Floor"
web-management management-url ""
time timezone -400
time daylight-time-rule Continental-US-and-Canada
module 1 type J86xxA
module 3 type J90XXA
trunk A2-A3 Trk1 Trunk
ip routing
vlan 1
untagged 1-8,10-15,17-24,A1,A4,Trk1
ip address
no untagged 9,16
vlan 11
name "IDF-1"
untagged 9
ip helper-address
ip address
vlan 12
name "IDF-2"
untagged 16
ip helper-address
ip address
no stack
no ip ssh
spanning-tree Trk1 priority 4
password manager
Honored Contributor

Re: Trouble with additional VLAN

you may look again at the dhcp-config instead of the switch-config
the dhcp-server knows nothing about vlans, and need not to be configured for vlans.
It must know about subnets!
the router ties subnets together.

- for each subnet you need to create a different scope
- each scope provides it subnet a range of adresses
- the gateway in a vlan/subnet is configured a ip-helper (which you did)
- each scope must supply the default gateway within its own subnet to the client.


hope this helps

Re: Trouble with additional VLAN

Thanks for the reply, Pieter.

I've re-examined my DHCP setup and feel pretty good about it.

After reviewing documentation again, I reconfigured both switches and seem to have things working. IDF 6 is a new facility, so I brought them up on VLAN 16, and then used a couple PC's to test other VLANs.

I suspect the issue I was having (moving my laptop from VLAN to VLAN for testing) is related to ARP cache and the switch's MAC database - I need to look into that.

My config is attached, and I'd like some feedback about providing routing services on the 2900-48 in addition to the 2900-24.

I'd like to have some redundancy, and I'd like to keep routing for the attached IDF's in the local switch rather than passing the traffic up to the 'main' switch.

2900-24 has four IDFs attached. 2900-48 has two IDFs attached. The two switches are connected via the two 10Gbps ports (trunked).

Honored Contributor

Re: Trouble with additional VLAN

ok so the dhcp-question is resolved?

and you have a new question about routing locally?

this should be no great problem.
to change the routing function for a single vlan from one switch to the other you simply have to exchange the "ip adress ..." and "no ip adress" rules for a vlan. (also move the "ip helper to the new router)

after that you need the routers to communicate. So on the second switch
add "ip routing" and add a default-route to reach the other subnets. (the should allready know about all subnets).
Honored Contributor

Re: Trouble with additional VLAN

i forgot to add something in my example
if you move the routing function of vlan13/ to the other switch
the the default gateway also needs to know about this
it now probably routes all trafic for vlan13/ to (switch-1)
this should be changed to (switch-2 as the new router for the subnet).

Re: Trouble with additional VLAN


Thanks again for your reply.

I've adjusted my config as you suggested and all seems to be well.

I appreciate your assistance!
Honored Contributor

Re: Trouble with additional VLAN

Glad to be of help, and thanks for the points.