---
title: Updating a Node's IPv4 Address and Domain Name
slug: updating-node-ipv4-and-domain
description: Two procedures — IC-OS reinstall and a non-disruptive dfx call — for updating the public IPv4 address and domain name of an existing node.
tags:
  - node-provider
  - maintenance
  - runbook
  - networking
  - ipv4
date: 2026-05-04
related:
  - node-provider-maintenance
  - node-networking-guide
  - node-domain-name-guide
  - changing-node-ipv6
---

Each node provider is asked to deploy at least two nodes with public
IPv4 addresses and registered domain names in every data center they
operate in — specifically on the first two nodes of the first
rack at each site. Beyond that pair, additional nodes can run on IPv6
only. See the
[Node Provider Networking Guide](/wiki/node-networking-guide/) for the
underlying rule.

This entry covers what to do when an IPv4 address or domain name has
to change for an existing node. There are two methods. Pick the one
that matches how the node was onboarded.

> [!NOTE]
> Each IPv4 address must be unique to one node. Do not reuse an IPv4
> address across machines.

## Prerequisites

- The IPv4 address, prefix length, and gateway provided by the data
  center.
- A registered domain name for the node — see the
  [Node Provider Domain Name Guide](/wiki/node-domain-name-guide/).
- Either physical access to the node and its installation USB
  (Method 1), **or** the `node_operator_private_key.pem` file
  (Method 2).

## Method 1 — IC-OS reinstall

Use this method for nodes onboarded with a Nitrokey HSM. The change
requires a fresh IC-OS install.

1. Follow the deployment guide for your generation:
   [Gen-2](/wiki/node-deployment-gen-2/) or
   [Gen-1](/wiki/node-deployment-gen-1/).
2. At step 6 of the guide, configure the new IPv4 address, prefix
   length, gateway, and domain name.
3. Reinstall IC-OS from the USB stick.
4. Repeat for each node, reconfiguring the USB stick between
   deployments — **each node must have a unique IPv4 address**,
   so a single USB image cannot be reused.

> [!TIP]
> Always use the latest IC-OS release for the reinstall. Older images
> may fail to deploy.

## Method 2 — `dfx` call (no redeployment)

Use this method for nodes onboarded without a Nitrokey HSM, using a
PEM-based node operator key.

### Step 1 — Import the node operator identity

```bash
dfx upgrade
dfx identity import node_operator node_operator_private_key.pem \
  --storage-mode=plaintext
```

### Step 2 — Set the variables

```bash
NODE_ID="xxxxx-xxxxx-xxxxx-xxxxx-xxxxx-xxxxx-xxxxx-xxxxx-xxxxx-xxxxx-xxx"
IPV4_PREFIX_LENGTH="xx"
IPV4_ADDRESS="xxx.xxx.xxx.xxx"
IPV4_GATEWAY="xxx.xxx.xxx.xxx"
DOMAIN="node.example.com"
```

### Step 3 — Update the IPv4 configuration and domain

```bash
dfx canister --network ic --identity node_operator \
  call rwlgt-iiaaa-aaaaa-aaaaa-cai update_node_ipv4_config_directly \
  "(record { ipv4_config = opt record { gateway_ip_addr = \"$IPV4_GATEWAY\"; prefix_length = $IPV4_PREFIX_LENGTH : nat32; ip_addr = \"$IPV4_ADDRESS\"}; node_id = principal \"$NODE_ID\" })"

dfx canister --network ic --identity node_operator \
  call rwlgt-iiaaa-aaaaa-aaaaa-cai update_node_domain_directly \
  "(record { node_id = principal \"$NODE_ID\"; domain = opt \"$DOMAIN\" })"
```

The target canister `rwlgt-iiaaa-aaaaa-aaaaa-cai` is the registry
canister.

### Removing IPv4 and domain settings

To clear the IPv4 configuration or domain (for example, when retiring
the public IPv4 role on a node), pass `null`:

```bash
dfx canister --network ic --identity node_operator \
  call rwlgt-iiaaa-aaaaa-aaaaa-cai update_node_ipv4_config_directly \
  "(record { ipv4_config = null; node_id = principal \"$NODE_ID\" })"

dfx canister --network ic --identity node_operator \
  call rwlgt-iiaaa-aaaaa-aaaaa-cai update_node_domain_directly \
  "(record { node_id = principal \"$NODE_ID\"; domain = null })"
```

## Related

- [Node Provider Maintenance Guide](/wiki/node-provider-maintenance/) — the parent runbook.
- [Node Provider Networking Guide](/wiki/node-networking-guide/) — why IPv4 is required on the first two nodes.
- [Node Provider Domain Name Guide](/wiki/node-domain-name-guide/) — registering and validating the domain.
- [Changing the IPv6 Addresses of Nodes](/wiki/changing-node-ipv6/) — the IPv6 counterpart, which is more disruptive.