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Confirming DHCP Works


Overview:

Trying to confirm that my cell and laptop will pickup the correct (static) DHCP address from the Juniper firewall.

Basic Configs:

Basic DHCP Configs:


These configs are already on the firewall, but are worth noting to make sure we understand what’s going on.

set system services dhcp router 192.168.1.1
# LEASE IP RANGE: 
set system services dhcp pool 198.18.2.0/24 address-range low 198.18.2.100
set system services dhcp pool 198.18.2.0/24 address-range high 198.18.2.149
# LEASE DETAILS: 
set system services dhcp pool 198.18.2.0/24 default-lease-time 3600
set system services dhcp pool 198.18.2.0/24 name-server 8.8.8.8
set system services dhcp pool 198.18.2.0/24 router 198.18.2.1

set security zones security-zone inside interfaces fe-0/0/1.12 host-inbound-traffic system-services dhcp

Define the MACs:


Set the static bindings for the Mac addresses as the following

set system services dhcp static-binding 8c:85:90:58:03:0f fixed-address 198.18.2.138
set system services dhcp static-binding 8c:85:90:58:03:0f host-name Dads_Mac
set system services dhcp static-binding f0:98:9d:e2:16:99 fixed-address 198.18.2.139
set system services dhcp static-binding f0:98:9d:e2:16:99 host-name Dads_phone

Testing after deploying:

Confirming DHCP Leases


View the bindings already on the firewall:

cmercier@srx100-a# run show system services dhcp binding
IP address       Hardware address   Type     Lease expires at
198.18.2.106     00:02:fd:04:71:40  dynamic  never
198.18.2.146     18:81:0e:1a:7e:44  static   never
198.18.2.102     18:b4:30:0a:5e:4c  dynamic  2019-06-29 03:49:13 UTC
198.18.2.118     1c:1a:c0:ac:34:65  dynamic  2019-06-29 03:48:08 UTC
198.18.2.120     20:df:b9:5e:30:bf  dynamic  2019-06-29 04:10:46 UTC
198.18.2.144     34:7c:25:32:8f:f7  static   never
198.18.2.109     50:32:37:ce:33:c2  dynamic  2019-06-29 04:11:16 UTC
198.18.2.125     5c:cf:7f:47:6c:38  dynamic  2019-06-29 04:10:28 UTC
198.18.2.105     60:01:94:a0:84:0c  dynamic  2019-06-29 03:47:40 UTC
198.18.2.145     74:9e:af:34:43:f3  static   never
198.18.2.126     74:e2:f5:be:d6:1c  dynamic  2019-06-29 04:05:04 UTC
198.18.2.143     74:e5:0b:32:54:0c  static   never
198.18.2.116     8c:85:90:58:03:0f  dynamic  2019-06-29 03:46:58 UTC
198.18.2.138     8c:85:90:58:03:0f  static   never
198.18.2.117     90:2e:1c:d0:6e:de  dynamic  2019-06-29 04:08:03 UTC
198.18.2.141     b4:ae:2b:f6:98:c6  static   never
198.18.2.140     b4:ae:2b:f6:98:c8  static   never
198.18.2.110     c4:b3:01:a2:5a:ba  dynamic  2019-06-29 03:51:21 UTC
198.18.2.103     dc:4f:22:3a:ef:01  dynamic  2019-06-29 04:13:02 UTC
198.18.2.113     f0:98:9d:e2:16:99  dynamic  2019-06-29 03:48:00 UTC
198.18.2.139     f0:98:9d:e2:16:99  static   never
198.18.2.142     f0:de:f1:81:09:4d  static   never
198.18.2.112     f8:95:ea:0c:55:86  dynamic  2019-06-29 04:08:23 UTC

[edit]
cmercier@srx100-a#

Clearing up duplicate leases


You might have the device bound to the dynamic lease, and not accepting the static lease:

cmercier@srx100-a# run show system services dhcp binding | match 16:99
198.18.2.113     f0:98:9d:e2:16:99  dynamic  2019-06-29 04:16:16 UTC
198.18.2.139     f0:98:9d:e2:16:99  static   never

[edit]
cmercier@srx100-a#

You can clear this out by clearing the lease on the DHCP server

cmercier@srx100-a# run clear system services dhcp binding 198.18.2.113

[edit]
cmercier@srx100-a#

and then renewing the IP (or rebooting) on the client system.

Trace Options:


send debug data to log files:

edit
set system services dhcp traceoptions file dhcp.dbg
set system services dhcp traceoptions flag all
commit
run show log dhcp.dbg

References:




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