Description

SRX Admin configures DHCP IP Pool for Dynamic IP assignment.

There are few Static reservations configured as well and the IPs are outside the Pool Range but inside the configured Network range.

Reviewing DHCP server bindings reveals that the reserved clients are getting the configured IPs where in it is outside the Pool range.

Symptoms

DHCP Pool Config:

set groups top routing-instances lan access address-assignment pool LAN-POOL family inet network 192.168.0.0/24

set groups top routing-instances lan access address-assignment pool LAN-POOL family inet range amr low 192.168.0.11

set groups top routing-instances lan access address-assignment pool LAN-POOL family inet range amr high 192.168.0.250

set groups top routing-instances lan access address-assignment pool LAN-POOL family inet dhcp-attributes maximum-lease-time 604800

set groups top routing-instances lan access address-assignment pool LAN-POOL family inet dhcp-attributes name-server 8.8.8.8

set groups top routing-instances lan access address-assignment pool LAN-POOL family inet dhcp-attributes name-server 1.1.1.1

 

Static Reservation:

set groups top routing-instances lan access address-assignment pool LAN-POOL family inet host File-Server ip-address 192.168.0.5 hardware-address 00:00:5E:00:53:00

set groups top routing-instances lan access address-assignment pool LAN-POOL family inet host Active-Directory ip-address 192.168.0.10 hardware-address 00:00:5E:00:53:0A

Solution

This is an expected behavior and working as per design.

 

DHCP IP Pool Range is used for Dynamically assigning IPs to clients for whom there are no static reservation configured.

 

If there is a static reservation configured (like in this scenario for File-Server and Active-Directory) the Network Check takes the precedence which makes 192.168.0.5 and 192.168.0.10 a valid IP to be assigned in the defined Network which is 192.168.0.0/24.

 

Also, this is the idle way of configuration as the statically reserved IPs should not be a part of the IP range to keep clear separation between Statically and Dynamically assigned IPs. By default, if there is a static reservation present, the assigned IP is removed/blocked from the Pool so that it wont be available for Dynamic Address Assignment.

Modification History

2026-04-30 : Article Created

Related Information

N/A