Re: [Nolug] Any VLAN experts out there?

I will attest to the fact that trunk configuration on the Dell
Powerconnect switches is a bit stupid and easy to goof up. I'll echo
what Dennis said - that would be where I would check first.

Another troubleshooting option is to eliminate the trunk. First,
disconnect the router from the second switch and reboot the cable
modem. On the first switch, where the modem is attached, setup an
untagged port on VLAN 10, connect a laptop and verify that you can
access the internet through just one switch. If that works, then the
trunk ports are probably your problem.

J

On 5/4/2011 3:25 PM, Dennis Bourn wrote:
> The modem will be trying to communicate directly with the router. The VLAN stuff is "hidden" from both of those devices if they are configured as you described, with their respective ports being untagged.
>
> The problem will likely be the trunk port between the switches. Are both using .1Q trunking? If you assign an IP address to vlan10 on the switches can you ping them from the sonicwall or vice versa. If no ping command is present, plug a laptop into the Untagged VLAN10 port and ping from there.
>
> Dennis Bourn
>
>
> -----Original Message-----
> From: owner-nolug@stoney.kellynet.org on behalf of Chris Jones
> Sent: Wed 5/4/2011 3:08 PM
> To: nolug@nolug.org
> Subject: Re: [Nolug] Any VLAN experts out there?
>
> Switches...one is a dell 2848 and the other is a "cisco small business"
> switch, router is sonicwall. Only the router and modem are on that vlan.
> As far as I can tell I've done everything by the book, all I can think of is
> the modem is trying to communicate directly with the router and it doesn't
> support "hops".
> On May 4, 2011 2:37 PM, "Jeremy"<listbox@unix-boy.com> wrote:
>> On 5/4/2011 2:13 PM, Chris Jones wrote:
>>> I'm running into an odd issue at one of my sites. We're trying to set
>>> them up with cable modem internet through charter, but we have some
>>> serious physical limitations to their network, which basically result
>>> in us having to set this up in a fairly complicated manner.
>>>
>>> We have 2 managed VLAN switches. One goes in each of 2 locations, and
>>> they will be linked together via uplink/stacking ports. Here's how
>>> the signal flow works:
>>>
>>> - Charter goes into a port untagged for VLAN10 on Switch A
>>> - Charter goes out thru the trunk port of Switch A that is tagged for
>>> all relevant VLAN's
>>> - Charter goes into the trunk port of Switch B
>>> - Charter goes out of an untagged port on Switch B and into the router
>>>
>>> Problem is, this is not working. It seems like the managed switches
>>> are doing something to the packets that the Charter modem does not
>>> like, screwing with MAC addresses or something. Does anyone know
>>> anything that may help me out here? Is there something I need to turn
>>> on in the switches to keep them from interfering with this traffic?
>> Are the cable modem and router the only devices in VLAN 10? Do you
>> have ANY other devices - PCs, servers, printers - in that VLAN?
>>
>> What type of switches and router are in the setup?
>>
>> J
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Received on 05/04/11