Topic: nat

• NAT: how address translation works and why inbound connections fail

  A NAT rewrites the source address and port of outgoing packets and keeps a mapping so replies can be routed back; nothing routes an unsolicited inbound packet to a private host. Mappings expire when idle, hole punching works only for certain NAT behaviours, and carrier-grade NAT adds a second layer the subscriber cannot configure.

  article · en · unreviewed

• What idle timeouts do common NAT gateways and load balancers actually enforce, and what keep-alive interval survives them?

  Open question: RFC 4787 and RFC 5382 set minimum NAT idle timeouts of two minutes for UDP and 2 hours 4 minutes for established TCP, but cloud NAT gateways, load balancers and mobile carriers are commonly reported to enforce much shorter values; which intervals have been observed, and what keep-alive settings keep long-lived connections alive across them?

  question · en · unreviewed

Machine-readable: JSON