set interfaces ge-0/0/0 unit 0 family inet dhcp
set interfaces ge-0/0/1 unit 0 family inet address 192.168.4.1/24
set interfaces st0 unit 0 family inet address 192.168.10.1/24

After configuring interface address now configure routing options for SRX device

set routing-options static route 192.168.100.0/24 next-hop st0.0
set routing-options static route 0.0.0.0/0 next-hop ge-0/0/0
Then configure the security zones and interfaces and inbound traffic.

set security zones security-zone untrust tcp-rst
set security zones security-zone untrust host-inbound-traffic system-services all
set security zones security-zone untrust interfaces ge-0/0/0.0
set security zones security-zone untrust interfaces st0.0
set security zones security-zone trust tcp-rst
set security zones security-zone trust host-inbound-traffic system-services all
set security zones security-zone trust interfaces ge-0/0/1.0

Let’s now configure phase 1 IKE configuration

set security ike proposal P1proposal authentication-method pre-shared-keys
set security ike proposal P1proposal dh-group group2
set security ike proposal P1proposal encryption-algorithm des-cbc
set security ike proposal P1proposal authentication-algorithm sha1
set security ike proposal P1proposal lifetime-seconds 86400
 
set security ike policy P1policy mode aggressive
set security ike policy P1policy proposals P1proposal
set security ike policy P1policy pre-shared-key ascii-text “p@ssword”
 
set security ike gateway P1gateway ike-policy P1policy
set security ike gateway P1gateway address 2.2.2.2
set security ike gateway P1gateway dead-peer-detection interval 10
set security ike gateway P1gateway dead-peer-detection threshold 3
set security ike gateway P1gateway local-identity user-at-hostname “bipin@mustbegeek.com”
set security ike gateway P1gateway external-interface ge-0/0/0

After configuring the phase 1 IKE, now configure phase 2 IKE configurations.

set security ipsec proposal P2proposal protocol esp
set security ipsec proposal P2proposal authentication-algorithm hmac-sha1-96
set security ipsec proposal P2proposal encryption-algorithm des-cbc
set security ipsec proposal P2proposal lifetime-seconds 36000
 
set security ipsec policy P2policy perfect-forward-secrecy keys group2
set security ipsec policy P2policy proposals P2proposal
 
set security ipsec vpn site1-to-site2-vpn bind-interface st0.0
set security ipsec vpn site1-to-site2-vpn ike gateway P1gateway
set security ipsec vpn site1-to-site2-vpn ike ipsec-policy P2policy
set security ipsec vpn site1-to-site2-vpn establish-tunnels immediately

Now create security policy to allow traffic from site1 to site2 and vice-versa.

set security policies from-zone trust to-zone untrust policy allowALL match source-address any
set security policies from-zone trust to-zone untrust policy allowALL match destination-address any
set security policies from-zone trust to-zone untrust policy allowALL match application any
set security policies from-zone trust to-zone untrust policy allowALL then permit
 
set security policies from-zone untrust to-zone trust policy fromInternet match source-address any
set security policies from-zone untrust to-zone trust policy fromInternet match destination-address any
set security policies from-zone untrust to-zone trust policy fromInternet match application any
set security policies from-zone untrust to-zone trust policy fromInternet then permit

Note: – Make sure that you have allowed both remote network 192.168.100.1/24 and 192.168.10.0/24 network for incoming traffic on the home network.