diff --git a/app/forms/ip-pool-range-add.tsx b/app/forms/ip-pool-range-add.tsx
index f3ec199c2e..a32671fbfd 100644
--- a/app/forms/ip-pool-range-add.tsx
+++ b/app/forms/ip-pool-range-add.tsx
@@ -9,7 +9,7 @@ import { useNavigate } from 'react-router-dom'
 
 import { useApiMutation, useApiQueryClient, type IpRange } from '@oxide/api'
 import { Message } from '@oxide/ui'
-import { IPV4_REGEX, IPV6_REGEX } from '@oxide/util'
+import { validateIp } from '@oxide/util'
 
 import { SideModalForm, TextField } from 'app/components/form'
 import { useForm, useIpPoolSelector } from 'app/hooks'
@@ -21,12 +21,6 @@ const defaultValues: IpRange = {
   last: '',
 }
 
-function validateIp(s: string) {
-  const isv4 = IPV4_REGEX.test(s)
-  const isv6 = !isv4 && IPV6_REGEX.test(s)
-  return { isv4, isv6, valid: isv4 || isv6 }
-}
-
 const invalidAddressError = { type: 'pattern', message: 'Not a valid IP address' }
 
 const diffVersionError = {
diff --git a/libs/util/str.spec.ts b/libs/util/str.spec.ts
index 629d2be1fd..37115bd02e 100644
--- a/libs/util/str.spec.ts
+++ b/libs/util/str.spec.ts
@@ -7,15 +7,7 @@
  */
 import { describe, expect, it, test } from 'vitest'
 
-import {
-  camelCase,
-  capitalize,
-  commaSeries,
-  IPV4_REGEX,
-  IPV6_REGEX,
-  kebabCase,
-  titleCase,
-} from './str'
+import { camelCase, capitalize, commaSeries, kebabCase, titleCase, validateIp } from './str'
 
 describe('capitalize', () => {
   it('capitalizes the first letter', () => {
@@ -88,29 +80,12 @@ describe('titleCase', () => {
 // Rust playground comparing results with std::net::{Ipv4Addr, Ipv6Addr}
 // https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=493b3345b9f6c0b1c8ee91834e99ef7b
 
-test.each(['123.4.56.7', '1.2.3.4'])('ipv4Regex passes: %s', (s) => {
-  expect(IPV4_REGEX.test(s)).toBe(true)
-})
-
-test.each([
-  '',
-  '1',
-  'abc',
-  'a.b.c.d',
-  // some implementations (I think incorrectly) allow leading zeros but nexus does not
-  '01.102.103.104',
-  '::ffff:192.0.2.128',
-  '127.0.0',
-  '127.0.0.1.',
-  '127.0.0.1 ',
-  ' 127.0.0.1',
-  '10002.3.4',
-  '1.2.3.4.5',
-  '256.0.0.0',
-  '260.0.0.0',
-])('ipv4Regex fails: %s', (s) => {
-  expect(IPV4_REGEX.test(s)).toBe(false)
-})
+test.each(['123.4.56.7', '1.2.3.4'])(
+  'validateIp catches valid IPV4 / invalid IPV6: %s',
+  (s) => {
+    expect(validateIp(s)).toStrictEqual({ isv4: true, isv6: false, valid: true })
+  }
+)
 
 test.each([
   '2001:db8:3333:4444:5555:6666:7777:8888',
@@ -129,15 +104,26 @@ test.each([
   '::ffff:255.255.255.255',
   'fe08::7:8',
   'ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff',
-])('ipv6Regex passes: %s', (s) => {
-  expect(IPV6_REGEX.test(s)).toBe(true)
+])('validateIp catches invalid IPV4 / valid IPV6: %s', (s) => {
+  expect(validateIp(s)).toStrictEqual({ isv4: false, isv6: true, valid: true })
 })
 
 test.each([
   '',
   '1',
   'abc',
-  '123.4.56.7',
+  'a.b.c.d',
+  // some implementations (I think incorrectly) allow leading zeros but nexus does not
+  '01.102.103.104',
+  '127.0.0',
+  '127.0.0.1.',
+  '127.0.0.1 ',
+  ' 127.0.0.1',
+  '10002.3.4',
+  '1.2.3.4.5',
+  '256.0.0.0',
+  '260.0.0.0',
+  '256.1.1.1',
   '2001:0db8:85a3:0000:0000:8a2e:0370:7334 ',
   ' 2001:db8::',
   '1:2:3:4:5:6:7:8:9',
@@ -151,6 +137,6 @@ test.each([
   'fe08::7:8%',
   'fe08::7:8i',
   'fe08::7:8interface',
-])('ipv6Regex fails: %s', (s) => {
-  expect(IPV6_REGEX.test(s)).toBe(false)
+])('validateIp catches invalid IP: %s', (s) => {
+  expect(validateIp(s)).toStrictEqual({ isv4: false, isv6: false, valid: false })
 })
diff --git a/libs/util/str.ts b/libs/util/str.ts
index 4c6fd9d95a..55cde1f7bb 100644
--- a/libs/util/str.ts
+++ b/libs/util/str.ts
@@ -54,8 +54,14 @@ export const titleCase = (text: string): string => {
 // but they didn't match results with std::new on simple test cases
 // https://github.com/fabian-hiller/valibot/blob/2554aea5/library/src/regex.ts#L43-L54
 
-export const IPV4_REGEX =
+const IPV4_REGEX =
   /^(?:(?:[1-9]|1\d|2[0-4])?\d|25[0-5])(?:\.(?:(?:[1-9]|1\d|2[0-4])?\d|25[0-5])){3}$/u
 
-export const IPV6_REGEX =
+const IPV6_REGEX =
   /^(?:(?:[\da-f]{1,4}:){7}[\da-f]{1,4}|(?:[\da-f]{1,4}:){1,7}:|(?:[\da-f]{1,4}:){1,6}:[\da-f]{1,4}|(?:[\da-f]{1,4}:){1,5}(?::[\da-f]{1,4}){1,2}|(?:[\da-f]{1,4}:){1,4}(?::[\da-f]{1,4}){1,3}|(?:[\da-f]{1,4}:){1,3}(?::[\da-f]{1,4}){1,4}|(?:[\da-f]{1,4}:){1,2}(?::[\da-f]{1,4}){1,5}|[\da-f]{1,4}:(?::[\da-f]{1,4}){1,6}|:(?:(?::[\da-f]{1,4}){1,7}|:)|fe80:(?::[\da-f]{0,4}){0,4}%[\da-z]+|::(?:f{4}(?::0{1,4})?:)?(?:(?:25[0-5]|(?:2[0-4]|1?\d)?\d)\.){3}(?:25[0-5]|(?:2[0-4]|1?\d)?\d)|(?:[\da-f]{1,4}:){1,4}:(?:(?:25[0-5]|(?:2[0-4]|1?\d)?\d)\.){3}(?:25[0-5]|(?:2[0-4]|1?\d)?\d))$/iu
+
+export const validateIp = (ip: string) => {
+  const isv4 = IPV4_REGEX.test(ip)
+  const isv6 = !isv4 && IPV6_REGEX.test(ip)
+  return { isv4, isv6, valid: isv4 || isv6 }
+}