topic RE: Many DHCP scopes on one VLAN segment - it that possible ? in Network Architecture & Design

Many DHCP scopes on one VLAN segment - it that possible ?

Robert_Zdzieblo — Fri, 16 Feb 2018 17:44:00 GMT

Hello Community !

I am wandering, if the following setup is possible to work:
1. We have a set (let's say 5) of typical /24 subnets.
2. There are separate DHCP pools defined for each subnet on single MS DHCP server.
3. We have a router configured for DHCP relaying for each subnet and separate, untagged interface for each vlan.

The goal is to have one 'big' network segment with single VLAN ID, having clients in this VLAN addressed with different scopes.

At first it seems that such network config is asking for trouble, but I've heard people saying that it worked for them.

The main problem is that subnet re-design is not an option.
The switching is pure EXOS, vlans routing is done using Juniper SRX.

Did you have any similar experiences ? Or do you have any ideas how to to it ?

Thanks in advance for any feedback...

Robert

RE: Many DHCP scopes on one VLAN segment - it that possible ?

Nick_Yakimenko — Fri, 16 Feb 2018 17:49:00 GMT

MS DHCP server knows mac-addresses of all devices that are connected?
What if a new device will be connected? From which scope will he get an IP?

RE: Many DHCP scopes on one VLAN segment - it that possible ?

Robert_Zdzieblo — Fri, 16 Feb 2018 18:02:00 GMT

I guess MS DHCP should know all MACs.
I don't know - there is one DHCP server and many scopes.
Maybe there is a way to direct specific DCHP pool traffic (or many pools) to one router interface ?

RE: Many DHCP scopes on one VLAN segment - it that possible ?

mp2014 — Fri, 16 Feb 2018 18:50:00 GMT

Maybe you're looking for "super scopes" on MS DHCP?

RE: Many DHCP scopes on one VLAN segment - it that possible ?

Robert_Zdzieblo — Fri, 16 Feb 2018 18:50:00 GMT

Sure, looks like it is about "super scopes" - thank you, mp2014 !

RE: Many DHCP scopes on one VLAN segment - it that possible ?

Hieu_Nguyen — Thu, 09 Sep 2021 03:23:00 GMT

It is possible but it still does not work for me. Help

I follow this

https://extremeportal.force.com/ExtrArticleDetail?an=000056776&q=dhcp%20super%20scope

And this

https://documentation.extremenetworks.com/EOS_CLI/S-K-Series/S-K-7100_CLI_Guide/r_ip_dhcp_relay_information_option_link_selection.shtml?_ga=2.180551463.1457752191.1630679678-1276880935.1624384570

and this is my setting

--------------------------------------------------------------------------

interface vlan.0.40
ip address 10.9.4.1 255.255.254.0 primary
ip address 10.9.14.1 255.255.254.0 secondary
ip helper-address 10.0.0.x
ip helper-address 10.9.0.xx
ip dhcp relay information option
ip dhcp relay information option link-selection 10.9.14.0 mac 1C1BB5BB5A44
ip dhcp relay information option link-selection 10.9.14.0 mac 5C3A45
no shutdown
exit

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