VLAN and fixed IPs

Doug Hughes doug at will.to
Thu Sep 28 13:39:38 UTC 2017


3rd for Option 82. Most switches DHCP relay agent will support this via
a command. The problem I ran into with the ISC DHCP option 82 was that I
could do it based upon circuit-id (switch port) or on switch ID
(sometimes IP address of switch, sometimes configurable to mac, or
sometimes to hostname, usually configurable), but trying many different
ways I could never get it to use both at the same time.

If your use case is simple on a single switch, or multiple switches
where the switch port is unique, it should work just fine.



On 9/28/2017 5:58 AM, Patrick Trapp wrote:
> Seconding Christian's suggestion if your relay agent will support it. 
>
> -----Original Message-----
> From: dhcp-users [mailto:dhcp-users-bounces at lists.isc.org] On Behalf Of Christian Kratzer
> Sent: Thursday, September 28, 2017 4:48 AM
> To: Users of ISC DHCP <dhcp-users at lists.isc.org>
> Subject: Re: VLAN and fixed IPs
>
> Hi,
>
> On Thu, 28 Sep 2017, Jan Lundmark wrote:
>>
>>
>> Hi,
>>
>> We have an application where we want the clients to  have fixed IPs and that the clients are all on the same subnet.
>> It is not practical for our application to use the MAC adresses of the clients.
>>
>> This configuration below will assign a somewhat fixed IP based on the VLAN  subnets but it is not exactly what we want.
>> The point is that we want each client to receive a fixed IP address based on their port in the switch.
> <snipp/>
>
> dhcp snooping on some switches is able to insert realay agent options into packets passing by even in pure l2 environments.
>
> You can then assign fixed ip based on option82 circuit-id or remote-id options.
>
> Greetings
> Christian
>



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