(OT) vlans and cisco switches and dhcp to my system

[Bart Silverstrim]

Martin Marcher wrote:
> Bart Silverstrim wrote:
>> The response I got was that the phones are on a separate VLAN.  I never
>> had an answer about how the switch would differentiate the computer
>> passing through the phone rather than directly into the drop.
> 
> (very high level)
> You can configure the dhcp server to (and/or not exclusive)
> 
> a) serve different ip ranges to different clients identified by mac address
> (or vendor name, or.....)

Don't think that's the case here, but I didn't configure it initially. 
We have 2 scopes configured on an Active Directory server, but I didn't 
see anywhere in the DHCP snapin to find where or how the scopes were 
being limited to what device/MAC/etc.  The closest I have dealt with 
that is creating reservations within scopes for particular MAC addresses 
to get a consistent IP.

> b) serve different ip ranges to different vlans

Same above, can't find where in the DHCP snapin I'd find how that works. 
  I don't deal with the phone system directly, the IT boss deals with it 
and any time he has a question about it it goes to a consultant company 
that did the initial install/maintenance agreement work on the 
Callmanager system (in fairness, we don't see them that often; it's not 
like my boss thinks the network is powered by magic despite how silly my 
questions must be making me look here...)

>> Anyone willing to try giving a summary of what had happened, what I'm
>> missing here?  I was just repeatedly told that the phones are on a
>> separate VLAN despite the proper address being "passed through" to the
>> computer when the computer was connected to the phone.  I thought VLANs
>> were port-specific on the switch.
> 
> not only, on switches/routers they will with a single port act like 2
> different networks if configured to do so (my guess is that it's more dhcp
> related than vlan actually)

I know that the computers aren't configured to pull anything specific 
from the network, but the phones I never configured before; my boss and 
the consultants did that and he configures new phones as they come in. 
I know he has to "add" them to Callmanager when a new phone comes in to 
configure the phone extension, MAC, etc. on Callmanager, and the phones 
boot up and download their settings from Callmanager when plugged in, so 
I guess it's possible that something in the template they configure 
themselves with is requesting a particular VLAN.

I was never told of anything special with the DHCP server and never saw 
any settings on it that would limit what is handed out to what type of 
system, just that there are 2 scopes set up.  Since I am normally 
working on the machine side of things (OS/application 
configuration/maintenance/etc.) rather than anything with the Cisco 
brand (I'd prefer learning the ins and outs of AIX before burning my 
mind with IOS scenarios if given the choice) I haven't taken the time to 
figure out how that system exactly was working.