NAT

Unlocking Erigon's Connectivity: How --nat Shapes Your Node's Network Reach and Performance

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