TOPIC NETWORKING
NAT how private IPs reach the internet
IN 10 SECONDS
Network Address Translation (NAT) maps multiple private IP addresses inside a local network to a single public IP address, allowing local resources outbound access while keeping them hidden from inbound traffic.
GOTCHA NAT gateways can exhaust source ports if thousands of connections are opened simultaneously. Keep-alives help reduce port churn.
HOW NAT TRANSLATION FLOWS
01 Private host sends a packet to a public IP from its private IP.
02 NAT Gateway intercepts the packet, replaces private source IP with its own public IP, and records the session.
03 Remote server replies to the NAT gateway's public IP.
04 NAT Gateway looks up the session table and translates the destination back to the private host.
POKE IT YOURSELF
curl ifconfig.me — check your public IP as seen behind NAT
ip route show — see your local routing gateway
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