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Frequent Contributor II

DHCP pool limit in 6.3

Hello

 

I just upgraded a customer to 6.3 because of the new RAP-155.

This customer has a few DHCP pools configured, it's part of their network structure.

I have told them that the supported/recommended limit for their 3400 controller is 512 hosts.

 

We have more than that for sure, and it has been running fine. Not all the scopes a lease out at any given time, by far.

 

In 6.3 the release notes clearly states the limits for each controller. But as i was about to add another scope, the limits seems to be impossible to move beyond.

I get an error saying that i can't add the pool, as there are more than 512 addresses in total configured already.

This will be a major issue, not with me i think.

 

We are planning a switch to a windows-based DHCP system, but for now the network/servers etc are not in place for this.

Is there any way around this limit?

 

Please help

 

Roar Fossen

Re: DHCP pool limit in 6.3

 

As you know this is not best practice.

 

But you could create another DHCP pool and then do VLAN pooling in your VAP with those 2 VLANs

Thank you

Victor Fabian
Lead Mobility Engineer @ Integration Partners
AMFX | ACMX | ACDX | ACCX | CWAP | CWDP | CWNA
Frequent Contributor II

Re: DHCP pool limit in 6.3

Hi

 

I painfully know that this is not the best practice, and i have told the customer several times, in LARGE letters.

But he has created a system of VLAN's and DHCP scopes for their company.

They have lots of branch offices, that are small, and usually runs just 1 RAP-5.

 

So we have several VLAN's and hence several DHCP scopes, not just 2-3-4, many.

Most of the scopes use just a few adresses.

 

Pre 6.3 this was not a problem, as the amount of leases was not that high.

 

When Aruba now has limited this, i'm kinda fubar. Will take me hours to clean up and change the overall structure.

If there is no way around this (turn of the check for the amount of leases programmed), i will most probably have to revert back to 6.1.3.6.

 

Roar Fossen

Re: DHCP pool limit in 6.3

 

 

Do you have more than 512 DHCP pools ?

Thank you

Victor Fabian
Lead Mobility Engineer @ Integration Partners
AMFX | ACMX | ACDX | ACCX | CWAP | CWDP | CWNA
Frequent Contributor II

Re: DHCP pool limit in 6.3

Hi

 

Nope, i don't have that many pools. But the 6.3 ArubaOS is now limited for 512 programmed hosts on a 3400 controller, i definitely have more than that.

 

This what the controller says

 

Failed to add pool Knarvik_WLAN which has 253 addresses. Maximum addresses configurable is 512.

Roar Fossen

Re: DHCP pool limit in 6.3

 

This looks to be something new in AOS 6.3 , to prevent issues :

 

 

I have attached the document that has this information

Thank you

Victor Fabian
Lead Mobility Engineer @ Integration Partners
AMFX | ACMX | ACDX | ACCX | CWAP | CWDP | CWNA
Frequent Contributor II

Re: DHCP pool limit in 6.3

Hi

 

Must be a new strategy. I have known about the potential problem of running more than 512 programmed hosts, but it was a calculated risk when we used more.

I'm not that very fond of being restricted, and not having the choice.

 

I don't have to delete the scopes i have, but i'm unable add more. Will just have to use the scopes that i have programmed, and plan a different setup.

 

Roar Fossen

New Contributor

Re: DHCP pool limit in 6.3

Hello

 

We have come across the same issue. We are about to upgrade all our OS versions and we have DHCP on the controller servicing our mobile fleet. This is a big problem for us.

 

What have other people done to get around this issue? does Aruba offer any guidance or have any solutions in place?

 

Any help or guidance would be appreciated.

 

ACMA

Cem Akilli

New Contributor

Re: DHCP pool limit in 6.3

We ran into this issue at our school and it has been nothing but headaches.  This is especially relevant given the transitive nature of our populace.  We have people show up for an hour and then leave.  We have set the DHCP lease time to 2 hours, (I wanted to set it to 1 but Aruba recommended not going that low for performance sake). 

 

I have found that even with the 2 hour window, those addresses don't always get released right at the 2 hour mark.  I have been running the command to clear all the leases on the controller and redistribute them to only truly active clients.  This is working ok, but can be a hassle.  The command is run via the CLI after logging into the "enable" account, you type "clear ip dhcp binding" without the quotes.  Users don't seem to notice a thing. 

 

Having an internal DHCP server was one of our selling points for getting Aruba, and we are sad to see this hard coded limit set(especially so low on the 3000 series).  If anyone has a support account navigate over to the IDEA Portal and Promote my "idea" to allow this to be upped.  Maybe they will listen.

 

Idea # -  IN-00003129

link - https://arubanetworkskb.secure.force.com/cp/ideas/viewIdea.apexp?id=08740000000LGHx

 

 

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