This article explains how to adopt SRX to mist and the basic configuration to get started. 

1. Configure basic configuration needed for SRX, ie interface IP config, zone configuration, route and name server configuration. 

Example:

root@SRX-TEST> show configuration |display set 
set version 23.4R2-S4.9
set system host-name SRX-TEST
set system root-authentication encrypted-password "$6$X1rdj4WW$Gj8bEvojQF3iJK1dp1sJU6TesZrgv6uZpURpQl8hvWoF75d9kXQpGPwsZlgkrk0CpJ8yl78Z1Zf1iSg6FrR9/."
set system services ssh root-login allow
set system name-server 8.8.8.8
set security zones security-zone untrust interfaces ge-0/0/1.0 host-inbound-traffic system-services all
set interfaces ge-0/0/1 unit 0 family inet address x.x.x.x/24
set routing-options static route 0.0.0.0/0 next-hop y.y.y.y

2. On mist, Either configure a New site for this specific wan edge or can use an existing site if already present. 

Organisation > Create Site 

3. Provide all necessary information on site configuration and majorly configure root password under Wan edges section ( This will be used as SRX root password ) 

4. Adopt SRX 

> On Mist > Organisation > Inventory > Wan Edges > Adopt Wan Edges > Copy the config 
> On SRX > Configure > load set terminal > paste the config > press 'enter' > press 'control + d' > "commit and-quit" 

5. Once commit is completed: 

On SRX run the below command, you should get the output as established. ( mist is connected on port 2200 )
root@SRX-TEST> show system connections | match 2200 
tcp4       0      0  10.219.156.31.62558                           34.193.120.45.2200                            ESTABLISHED

On Mist : Refresh the webpage, so that the device shows up on Mist inventory 
The device will show up as unassigned. 

6. Select the device > click on 'more' > Select 'Assign to Site' 

7. Select the site needed and click on "Assign to Site" 
Note: do not use manage configuration by mist unless you have a template assigned to the site which will push all the necessary config to SRX.

8. Navigate to Wan edges > Select the right site name 
You should see the device in connected state 

9. Open the Wan edge and do the below configurations bare minimum configuration. 

> Configure a device host name 
> Configure DNS Settings 
> Add a wan interface 
> If you still need SSH access to the SRX via putty of Secure CRT, configure the below in additional cli ( you can remove it later as per your business requirements)
Note: 'wan0' is the name which is given for the wan interface in test setup and interface ge-0/0/1 is used for internet connectivity for SRX, you have to configure accordingly as per your device config. 

Example:
set security zones security-zone wan0 interfaces ge-0/0/1.0 host-inbound-traffic system-services ssh    
set security zones security-zone wan0 interfaces ge-0/0/1.0 host-inbound-traffic system-services ping   
set system services ssh root-login allow

10. Save the config on Mist > click on 'enable Configuration Management' > click save 

If you face any issues, please contact JTAC for further assistance.