┌───────┐ ║ ┌─────┐ ║ ┌──────┐ Network │TelBru │ ║ │Modem│ ║ │ WiFi │ Connections │ WAN │◀───────────────────╬─────────▶│ │◀──────────╬─────────────────▶│Router│ └───────┘ ║ └─────┘ ║ └──────┘ ║ ║ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╬ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─║─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ║ ║ ║ ║ ║ Outgoing connections ║ ║ work correctly ║ ◀━━━━━━━━━━━━━━━━━━━━━━━━━━╬━━ through both firewalls ━━╬━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓ ║ (double NAT'ing) ║ ┃ ║ ║ ▼ ║ ║ ╔═══════╗ ║ ║ ║ LAN ║ ║ ║ ║Clients║ ║ ║ ╚═══════╝ ║ Incoming protocols ║ ▲ ║ require port ║ ┃ VPN ◀━━━━━━━━━━━━━━━━━━━━━━╬━━━━ forwarding setup ━━━━╬━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┫ Firewall Configuration ║ on both firewalls ║ ┃ and traffic routing ║ ║ ┃ ║ ║ ┃ ┌───────────────────────────┐ ║ ║ ┃ │ Internet entities making │ ║ Incoming connections ║ UPnP requests ┌─────────────┐ │inbound connections ,i.e.,:│ ║ can't be setup with ║ only puncture │Plex, Online │ │ Plex client, VOIP peer, │◀━┳────────────╬──┼UPnP (port forwarding─ ─ ╬ ─ the first ─ ─│Gaming, VOIP │ │ gaming peer │ ┃ ║ must be manually ║ firewall and └─────────────┘ └───────────────────────────┘ ┃ ║ configured) ║ will not work ▲ ┃ ║ ║ ┃ ┃ ║ Incoming connections ║ ┃ ▼ ║ can be automatically ║ ┃ ┌─────────────────┐ ║ established by ║ ┃ │ Intermediary │ ║ software designed to ║ ┃ │ Internet relay; │ ║ work around firewalls ║ ┃ │ more delay, │◀──╬─── blocking incoming ━━━╬━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛ │ less throughput │ ║ connections by first ║ └─────────────────┘ ║ setting up an outgoing ║ connection to an intermediary entity Workable for technically the proficient. Outgoing connections will just "work". Incoming connections can only be established via intermediaries; even when such services are available delay will higher and throughput lower.