SNMP V1 and V2c

set snmp location "Text String That Indicates Where This Is At"
set snmp contact "usually@MyEmail.com"
set snmp community MyCommunityString authorization read-only
set snmp community MyCommunityString clients ip.addresses.allowed.access/24
set snmp community MyCommunityString clients moreip.addresses.allowed.access/24

SNMP V3

set snmp location "My Server Room"
set snmp contact "hostmaster@myemail.com"
set snmp v3 usm local-engine user SNMPUSER authentication-md5 authentication-password "MyMD5Password"
set snmp v3 usm local-engine user SNMPUSER privacy-aes128 privacy-password "MyDESPassword"
set snmp v3 vacm security-to-group security-model usm security-name SNMPUSER group SNMPV3GROUP
set snmp v3 vacm access group SNMPV3GROUP default-context-prefix security-model any security-level privacy read-view SNMPVIEW
set snmp view SNMPVIEW oid .1 include

Update 2022/04/06 – update snmp v3 to use aes128

Tested on Juniper SRX300 running version 15.1X49-D211