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Forum Discussion
Edit/Add new IP reservations
I have an RBR50v2 Orbi router and 2 satellites with FW ver 2.7.5.6. I have entered 15, or so, reserved internal IP addresses using "Advanced > Security > Access Control". All works well. The is...
There are differing opinions on the best way to manage the "range" of the DHCP process.
My opinion is this:
- Reserved IP addresses should not be part of the DHCP "pool". Suppose a device with a reserved IP address is not currently connected to the network (perhaps a mobile phone) and some other random device connects and makes a DHCP request. These is a possibility that this device may be assigned the IP that was supposed to be reserved for that phone. What happens if the phone now appears and asks to connect? It cannot have the reserved IP because some other device already has it.
- The DHCP "pool" should be large enough to handle devices which connect to the network and do not have reserved IP addresses.
- In my case, IPs from 192.168.1.2 through 192.168.1.100 are set aside for reserved addresses and IPs from 192.168.1.101 to 192.168.1.150 are in the "pool". IPs from 192.168.1.151 through 192.168.1.254 are not defined.
- I definitely endorse reserving IP addresses for satellites, printers, NAS devices, etc.
(being a wee bit OCD) I reserve IP addresses for every device which is expected to be connected to the network and have set aside groups of IPs for types of devices (cameras, smart plugs, etc.)
My LAN Setup table currently has 59 devices.
So the "pool" is defined by "Use Router as DHCP Server" with a Starting and Ending IP Address range? And the "undefined" range is not used at all, correct?
FYI, Been a long standing standard networking practice for a long time, IP address RESERVATIONSs should be with in the DHCP IP ADDRESS POOL, i.e. 192.168.1.100 to 192.168.1.200 can be a pool range. STATIC IP addresses are set ON devices and are set outside of the DHCP IP ADDRESS POOL range. Either side of the afore mentioned example range is out side of the pool and can be used by STATIC IP addressed devices. IP address reservations are handled and managed by the DHCP service inside the pool, not outside of it. How it's designed. IP addresses are first Dynamically handed out to devices making a connection. If an IP address is already taken by another, then the next 1st available address it given out. Even if the IP address is already RESERVED in the DHCP pool range, then the next availble IP address is given out by the DHCP serivce, regardless if it's Dynamic or Reserved. How the DHCP system works and intended how to work for most home class router systems.
So the "pool" is defined by "Use Router as DHCP Server" with a Starting and Ending IP Address range? And the "undefined" range is not used at all, correct?
https://kb.netgear.com/25722/How-do-I-reserve-an-IP-address-on-my-NETGEAR-router
Even if the IP address is already RESERVED in the DHCP pool range, then the next availble IP address is given out by the DHCP serivce, regardless if it's Dynamic or Reserved.
I don't think this bit is correct. The reserved IP address is locked to a specific MAC address, and should not be given out to any other device.
If it didn't work this way, then rebooting the router would result in a big mess. The client devices request addresses in a pretty random order, so the reservations would largely be ignored.
While keeping the reserved addresses out of the pool eliminates any possibility of the DHCP server assigning a different address, this extra precaution really shouldn't be necessary. For instance, see this tutorial:
- https://www.manageengine.com/products/oputils/tech-topics/dhcp-reservation.html
- IP address reservation: Once you have identified the MAC address of the device, reserve IP addresses for each MAC address in the DHCP management console. This involves associating the MAC addresses within a fixed IP address in DHCP server's IP pool.
Reserved IP addresses should not be part of the DHCP "pool".
FWIW, I also keep them out of the pool. But I'd consider it a bug if the router were to assign a reserved address to a different device - even if the reserved address is not connected at the time.
I definitely endorse reserving IP addresses for satellites, printers, NAS devices, etc.
You should reserve the IP address for any destination of a port forwarding rule.
I reserve NAS, printers, desktop PCs connected over ethernet, and smart/managed switches.
So the "pool" is defined by "Use Router as DHCP Server" with a Starting and Ending IP Address range? And the "undefined" range is not used at all, correct?
Yes. Though "undefined" just means that CrimpOn has chosen not to reserve those addresses. Note the last address in the subnet (.255) is a broadcast address, so should not be used for any client.
