Home: https://opnsense.org/

Documentation: https://docs.opnsense.org

Forums: https://forum.opnsense.org

NAT: https://docs.netgate.com/pfsense/en/latest/config/advanced-firewall-nat.html

Configuring NAT for VoIP Phones: https://docs.netgate.com/pfsense/en/latest/recipes/nat-voip-phones.html

Configuring NAT for a VoIP PBX: https://docs.netgate.com/pfsense/en/latest/recipes/nat-voip-pbx.html

Settings for VoIP: https://support.onsip.com/hc/en-us/articles/204029430-PFSense-Firewall-Settings-for-VoIP

UDP Timeouts: https://www.reddit.com/r/opnsense/comments/vr1zop/firewall_optimization_setting/

Research before using:

• Firewall → Settings → Normalization (Enable IP Do-Not-Fragment)
• Firewall → Settings → Firewall Optimization (Change to Conservative)

Low Throughput: https://forum.proxmox.com/threads/proxmox-pfsense-vm-extreme-low-throughput.67281/post-526005