On the EX:
root@EX4200_TOR_SELab> show configuration interfaces ge-3/0/16 | display set
set interfaces ge-3/0/16 description SRX300-1
set interfaces ge-3/0/16 unit 0 family ethernet-switching vlan members SE_OOB
set access address-assignment pool SkyEntDHCP family inet network 172.30.95.128/25
set access address-assignment pool SkyEntDHCP family inet range RANGE low 172.30.95.208
set access address-assignment pool SkyEntDHCP family inet range RANGE high 172.30.95.208
set access address-assignment pool SkyEntDHCP family inet dhcp-attributes name-server 8.8.8.8
set access address-assignment pool SkyEntDHCP family inet dhcp-attributes router 172.30.95.129
set access address-assignment pool SkyEntDHCP family inet host SkyEntSRX300 hardware-address 30:b6:4f:21:02:80
set access address-assignment pool SkyEntDHCP family inet host SkyEntSRX300 ip-address 172.30.95.208
On the SRX:
set interfaces ge-0/0/2 unit 0 family inet dhcp
set security zones security-zone untrust screen untrust-screen;
interfaces fe-0/0/2.0 host-inbound-traffic system-services dhcp