Re: [Nolug] Any VLAN experts out there?

From: Chris Jones <techmaster_at_gmail.com>
Date: Wed, 4 May 2011 17:12:28 -0500
Message-ID: <BANLkTikW8ZjQaFUPXCVVgyouSKO4d463Ng@mail.gmail.com>

I did notice that one of the switches you can actually set a port as being a
"trunk" and on the other one you don't. It has access ports and a few other
types, but for a trunk you apparently just tag whatever vlan's go on it.
Come to think of it, I have the modem going into one VLAN10 port, but there
is a 2nd VLAN10 port next to that one to give us a spare. I plugged into
that with my laptop and I was able to get out. Well, if you two are
thinking that it's something to do with the trunk, I might add that the
trunk link between the two switches is going over a Ubiquiti Nanobridge M5.

On Wed, May 4, 2011 at 4:48 PM, Jeremy <listbox@unix-boy.com> wrote:

> 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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>>
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