hashicorp/vagrant · warning

You assigned a static IP ending in ".1" or ":1" to this mach

Error message

You assigned a static IP ending in ".1" or ":1" to this machine.
This is very often used by the router and can cause the
network to not work properly. If the network doesn't work
properly, try changing this IP.

What it means

During private_network validation, a static IP whose string ends with ".1" or ":1" (and whose type is not dhcp) draws this warning. The first address of a subnet conventionally belongs to the router/gateway, so assigning it to a guest very often breaks networking; it is only a warning and the config still validates.

Source

Thrown at plugins/kernel_v2/config/vm.rb:930

              end

              fp_used.add(key)
            end

            if !port_range.include?(options[:host]) || !port_range.include?(options[:guest])
              errors << I18n.t("vagrant.config.vm.network_fp_invalid_port")
            end
          end

          if type == :private_network
            if options[:type] && options[:type].to_sym != :dhcp
              if !options[:ip]
                errors << I18n.t("vagrant.config.vm.network_ip_required")
              end
            end

            if options[:ip] && (options[:ip].end_with?(".1") || options[:ip].end_with?(":1")) && (options[:type] || "").to_sym != :dhcp
              machine.ui.warn(I18n.t(
                "vagrant.config.vm.network_ip_ends_in_one"))
            end
          end
        end

        # Validate disks
        # Check if there is more than one primary disk defined and throw an error
        primary_disks = @disks.select { |d| d.primary && d.type == :disk }
        if primary_disks.size > 1
          errors << I18n.t("vagrant.config.vm.multiple_primary_disks_error",
                           name: machine.name)
        end

        disk_names = @disks.map { |d| d.name }
        duplicate_names = disk_names.find_all { |d| disk_names.count(d) > 1 }
        if duplicate_names.any?
          errors << I18n.t("vagrant.config.vm.multiple_disk_names_error",
                           name: machine.name,

View on GitHub (pinned to 35f3160f4a)

Solutions

1. Move the address up in the subnet, e.g. 192.168.33.2 or higher for the guest
2. Switch the network to dhcp (options[:type] = :dhcp) so no static IP is needed and the check is suppressed
3. Keep the .1/:1 address only if the machine intentionally acts as the router, and accept the warning

Example fix

# before
config.vm.network "private_network", ip: "192.168.33.1"
# after
config.vm.network "private_network", ip: "192.168.33.10"

# Vagrantfile-side check while composing networks
ip = "192.168.33.1"
warn "looks like a gateway address" if ip.end_with?(".1") || ip.end_with?(":1")

gateway_like_ip = ->(ip) { ip.to_s.end_with?(".1") || ip.to_s.end_with?(":1") }

When it happens

Trigger: `config.vm.network "private_network", ip: "192.168.33.1"` or an IPv6 form like `ip: "fd00::1"` where options[:type] is not :dhcp.

Common situations: Copying the gateway address from router docs into the Vagrantfile; habit of using .1 as a host address; example IPs pasted without editing.

Related errors

• There was an error while downloading the metadata for this b
• Vagrant failed to load a configured plugin source. This can
• The Vagrant Cloud server is not currently accepting connecti
• The Docker provider is unable to connect the container to th
• The Docker provider was unable to configure networking using

AI-assisted analysis of hashicorp/vagrant@35f3160f4a (2026-08-21). Data as JSON: /api/errors/e03615ea2ae6ab05. Report an issue: GitHub.