IPSEC VPN Configuration: Strongswan 5.9 & Juniper SRX1500

Site-to-Site IPSEC VPN Configuration between Two Gateways (Strongswan 5.9 & Juniper SRX1500)

Project Description:
We need an experienced network/security engineer to configure and establish a site-to-site IPSEC VPN tunnel between our two gateways — one running Strongswan 5.9 (NivaaSoft) and the other Juniper SRX1500 (Muni).
The configuration details and parameters are already defined (attached reference sheet). The goal is to successfully establish a secure, stable VPN tunnel for data exchange between both sites.
Technical Details (Summary):
VPN Type: Site-to-Site IPSEC
Endpoint 1: Strongswan 5.9 (Public IP: 65.108.5.249)
Endpoint 2: Juniper SRX1500 (Public IP: 41.79.48.123)
IKE Version: IKEv2
Authentication: Pre-shared key
Encryption: AES256
Integrity: SHA256
DH Group: 14
Timers: IKE = 86400s, IPSEC = 3600s
Perfect Forward Secrecy (PFS): Disabled
Encryption Domain/Subnets:
NivaaSoft: 192.168.101.2
Muni: 10.220.15.0/24
Scope of Work:
Configure IPSEC VPN on both ends (Strongswan & Juniper SRX1500).
Validate tunnel establishment and test connectivity between both subnets.
Provide step-by-step configuration documentation and commands used.
Suggest best practices for stability and security optimization.
Optional: Assist in creating monitoring/logging setup for tunnel uptime.
Requirements:
Proven experience with Juniper SRX firewall and Strongswan on Linux.
Strong understanding of IPSEC/IKEv2 configurations and troubleshooting.
Ability to work remotely via secure access or provide configuration scripts.
Fluent in English for clear documentation and communication.
Deliverables:
Working VPN tunnel between both sites.
Configuration script or commands for both sides.
Verification report showing successful ping/traffic exchange.
Budget: Open to reasonable quotes based on expertise and turnaround time.
Timeline: Preferably within 2–3 days from award.