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NAT

What --nat really controls​

The --nat option controls how Erigon advertises its external address to other peers in the Ethereum P2P network.

It does not:

  • open firewall ports for you
  • guarantee inbound connectivity by itself
  • directly control peer count

Instead, it determines whether other nodes can initiate inbound connections to your node, which has a significant impact on:

  • peer diversity (inbound vs outbound)
  • transaction gossip freshness
  • block content quality for validators and block producers

Why NAT configuration matters more than peer count​

Ethereum P2P is bidirectional:

  • your node connects outbound to peers
  • other nodes may connect inbound to you

Nodes that are reachable from the internet (i.e. correctly advertised via NAT) tend to:

  • receive transactions earlier
  • receive a wider variety of transactions
  • maintain a healthier “pending” transaction pool

For validators and block producers, this directly affects:

  • transaction inclusion
  • gas usage
  • likelihood of producing empty or low-gas blocks

A high peer count alone does not guarantee good transaction propagation if most peers are outbound-only.

NAT modes explained (practical behavior)​

nat: none​

Disables external address advertisement.

Erigon will not advertise a reachable address to peers. In practice, this often results in:

  • mostly outbound connections
  • few or no inbound peers
  • delayed or stale transaction gossip

Important: nat: none is generally not recommended for validators or block producers, even if peer count appears high. It is primarily suitable for:

  • private networks
  • non-proposing archive / RPC nodes
  • restricted environments where inbound connectivity is intentionally disabled

nat: extip: (recommended for datacenters & VPS)​

Explicitly advertises the given public IPv4 address to peers.

This is the most reliable and deterministic option when:

  • your node has a stable public IPv4 address
  • required P2P ports are open in the firewall

Benefits:

  • enables inbound peer connections
  • improves transaction gossip freshness
  • leads to healthier txpool “pending” state
  • strongly recommended for validators

Example:

nat: "extip:203.0.113.114"

nat: any​

Enables automatic NAT detection (e.g. UPnP / NAT-PMP where available).

Suitable for:

  • home networks
  • environments where the external IP is not known in advance

Less deterministic than extip, but generally better than none.

nat: stun​

Uses STUN to discover the external address.

Useful when:

  • running behind NAT
  • no UPnP is available
  • external IP cannot be configured manually