DHCP reservation

[attilay2k]

good evening everyone
I created my dhcp pools, but now I have about twenty devices to which I have to set a fixed ip address, via reservation.

The M4100 allows the creation of a maximum of 16 pools, I have read in some posts that there is the possibility to create the reservation via CLI but I have not found any documentation about it; can anyone tell me where I find it?

Thanks in advance

[LaurentMa · Accepted solution]

Hi @attilay2k 

Sorry to be the messenger for the news below

You are right, one static binding per DHCP pool, and maximum number of DHCP pools in M4100 is 16.

So we can only get one DHCP pool for your dynamic addresses and 15 static binding's using the pools 2-16.

For your information, the maximum number of DHCP pools can be found in the Platform Constants section of the Tech Specs in the M4100 datasheet.

The M4300 switches offer 256 pools and would help you.

Maybe  you could consider the new M4250 switches, they also offer 256 pools.

Datasheet 

There is model called M4250-10G2F-PoE+ (GSM4212P-100NAS in the US) with 10x1G ports and 2xSFP uplinks

I hope this helps!

Regards,

[JohnC_V]

@attilay2k,

I hope this article will help you configure DHCP reservations on your managed switch. Please check the link here.

Regards,

John

NETGEAR Community Team

[attilay2k]

thanks @JohnC_V 

I had already seen this post, but it is not clear to me if by acting in this way I can exceed the limit of 16 pools (i.e. if I can add more clients to the pool_manual) or if that limitation remains

[JohnC_V]

@attilay2k,

The limitation remains even though you use CLI to have a DHCP Reservation. This is a device limitation and not just a GUI limitation.

Hope it helps 🙂

Regards,

John

NETGEAR Community Team

[schumaku]

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@attilay2k wrote:

thanks @JohnC_V 

I had already seen this post, but it is not clear to me if by acting in this way I can exceed the limit of 16 pools (i.e. if I can add more clients to the pool_manual) or if that limitation remains

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Not sure I get you right - are you mixing max number of possible DHCP pools with the number of clients?

[attilay2k]

hi @schumaku 

maybe I didn't express myself well

i have 8 vlans to serve, so i created 8 dhcp pools

within some of the above 8 dhcp pools, I would like to make reservations to ensure that some of the devices that are in the above vlan always have the same ip address (so these are the clients)

from what I understand it is possible to make a reservation by creating a new "manual" type dhcp pool with the ip address that I want to assign to the client, but this way obviously quickly saturates the number of available dhcp pools (16)

is there another way to make reservations and guarantee (to about 20 devices) to always have the same ip?

[schumaku]

You create (or already have) one DHCP Pool per subnet, able to assign address for that very same subnet. You can add many static IP-MAC pairs into that same DHCP Pool - most likely more than you ever need.

[attilay2k]

@schumaku 

thanks for your feedback

but can you please explain me how to add static IP-MAC pairs? via CLI or WebInterface, as you prefer

each example i'd found won't let me create the association or give me an error message

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[schumaku]

You can use the Web UI or the CLI as referenced before https://kb.netgear.com/21933/How-do-I-configure-a-Dynamic-Host-Configuration-Protocol-DHCP-reservati... - the point is the somewhat miselading documentation - you don't create a new pool for each new entry. The "manual-pool" is the pool where you can add multiple entries ...

[attilay2k]

hi @schumaku 

i tried, but get the following error

(M4100-D12G) >enable
(M4100-D12G) #config
(M4100-D12G) (Config)#service dhcp
(M4100-D12G) (Config)#ip dhcp pool pool_manual
(M4100-D12G) (Config-dhcp-pool)#client-name myphone1
(M4100-D12G) (Config-dhcp-pool)#hardware-address 46:24:XX:XX:XX:XX
(M4100-D12G) (Config-dhcp-pool)#host 10.XX.XX.16 255.255.255.0
(M4100-D12G) (Config-dhcp-pool)#client-identifier 01:46:24:XX:XX:XX:XX
(M4100-D12G) (Config-dhcp-pool)#client-name myphone2
(M4100-D12G) (Config-dhcp-pool)#hardware-address 66:02:XX:XX:XX:XX
Couldn't set hardware address.

now in the web gui i see the new "pool_manual" with the myphone1 informations

[schumaku]

Looks like i'm wrong, and these CLI are similar to the goodl ol'IOS routers where we had to configure one pool per computer/MAC/client-identifier.

@LaurentMa are these legay switches within your comfort zone?  

[attilay2k]

Hi @schumaku , @LaurentMa 

any news for me?

[LaurentMa · Accepted solution]

Hi @attilay2k 

Sorry to be the messenger for the news below

You are right, one static binding per DHCP pool, and maximum number of DHCP pools in M4100 is 16.

So we can only get one DHCP pool for your dynamic addresses and 15 static binding's using the pools 2-16.

For your information, the maximum number of DHCP pools can be found in the Platform Constants section of the Tech Specs in the M4100 datasheet.

The M4300 switches offer 256 pools and would help you.

Maybe  you could consider the new M4250 switches, they also offer 256 pools.

Datasheet 

There is model called M4250-10G2F-PoE+ (GSM4212P-100NAS in the US) with 10x1G ports and 2xSFP uplinks

I hope this helps!

Regards,

[attilay2k]

Thanks