diff --git a/.size-limit.json b/.size-limit.json
index 02f2520..6bd29a0 100644
--- a/.size-limit.json
+++ b/.size-limit.json
@@ -9,7 +9,7 @@
       "LICENSE",
       "package-main.json"
     ],
-    "limit": "60.40 kB",
+    "limit": "61.052 kB",
     "brotli": false,
     "gzip": false
   },
@@ -18,7 +18,7 @@
     "path": [
       "target/*/core.*"
     ],
-    "limit": "41.25 kB",
+    "limit": "41.55 kB",
     "brotli": false,
     "gzip": false
   },
@@ -32,7 +32,7 @@
       "LICENSE",
       "package-main.json"
     ],
-    "limit": "18.30 kB",
+    "limit": "18.55 kB",
     "gzip": true
   },
   {
@@ -40,7 +40,7 @@
     "path": [
       "target/cjs"
     ],
-    "limit": "25.40 kB",
+    "limit": "25.55 kB",
     "brotli": false,
     "gzip": false
   },
@@ -49,14 +49,14 @@
     "path": [
       "target/esm"
     ],
-    "limit": "21.00 kB",
+    "limit": "21.15 kB",
     "brotli": false,
     "gzip": false
   },
   {
     "name": "libdefs",
     "path": "target/dts",
-    "limit": "7.15 kB",
+    "limit": "7.16 kB",
     "brotli": false,
     "gzip": false
   }
diff --git a/README.md b/README.md
index 7f2c25f..00f2b0a 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,19 @@ Temporary workaround to avoid refactoring is using `overrides` / `resolutions` i
 
 Browser-compatible core build is available as `@webpod/ip/core`: it omits `node:os` dependency and polyfills the `Buffer` API.
 
+### Strict mode
+By default, the library is in the `strict` mode that rejects non-canonical embedded IPv4 in IPv6. Switch to legacy flow if needed:
+
+```ts
+import { Address } from '@webpod/ip'
+
+Address.from('::ffff:5.6.7.8')    // ok
+Address.from('1:2:3:4::5.6.7.8')  // throws
+
+Address.strict = false
+Address.from('1:2:3:4::5.6.7.8')  // now it's fine
+```
+
 ## Usage
 The API is fully compatible with the latest `ip@2.0.1` but enforces stricter validations. See [coherence.md](./COHERENCE.md) for details.
 
diff --git a/src/main/ts/core.ts b/src/main/ts/core.ts
index d1e32c4..41c9f38 100644
--- a/src/main/ts/core.ts
+++ b/src/main/ts/core.ts
@@ -157,6 +157,8 @@ export class Address {
     return o
   }
 
+  static strict = true
+
   static from(raw: Raw): Address {
     if (raw instanceof Address) return this.create(raw.big, raw.family, raw.raw)
     if (typeof raw === 'string') return this.fromString(raw.toLowerCase())
@@ -334,18 +336,18 @@ export class Address {
     if (addr === '0') return this.create(0n, 4, addr)
 
     return addr.includes(':')
-      ? this.fromIPv6(addr)
+      ? this.fromIPv6(addr, this.strict)
       : this.fromIPv4(addr)
   }
 
-  private static fromIPv6(addr: string): Address {
+  private static fromIPv6(addr: string, strict?: boolean): Address {
     const al = addr.length
     const sep = addr.indexOf('::')
     if (
       al > IPV6_LEN_LIM ||
       sep !== -1 && addr.indexOf('::', sep + 1) !== -1 // only one '::' allowed
     )
-      throw new Error(`Invalid address: ${addr}`)
+      throw new Error(`Invalid address0: ${addr}`)
 
     const groups: number[] = []
     let p = 0, gc = -1
@@ -360,15 +362,16 @@ export class Address {
         if (sep === -1 || (end !== sep && end !== sep + 1 + +last))
           throw new Error(`Invalid address: ${addr}`)
         gc = groups.length
-      } else if (last && v.includes('.')) {
-        // embedded IPv4
-        if (
-          groups.length > 6 ||
+      } else if (last && v.includes('.')) { // embedded IPv4
+        if (gc === -1 ? groups.length !== 6 : groups.length > 5)
+          throw new Error(`Invalid address: ${addr}`)
+
+        if (strict && (
           gc === groups.length ||
-          (gc === -1 && groups.length !== 6) ||
           groups[groups.length - 1] !== 0xffff ||
           groups.slice(0, -1).some(x => x !== 0)
-        ) throw new Error(`Invalid address: ${addr}`)
+        ))
+          throw new Error(`Invalid address: ${addr}`)
 
         const long = Address.normalizeToLong(v, true)
         if (long === -1) throw new Error(`Invalid address: ${addr}`)
@@ -382,7 +385,7 @@ export class Address {
       p = i + 1
     }
     const offset = 8 - groups.length
-    if (gc === -1 ? offset !== 0 : offset < 1) throw new Error(`Invalid address: ${addr}`)
+    if (gc === -1 ? offset !== 0 : offset < 1) throw new Error(`Invalid address4: ${addr}`)
 
     let big = 0n
     for (let i = 0; i < 8; i++) {
diff --git a/src/test/js/export.test.js b/src/test/js/export.test.js
index a3ec4ad..5ae65ac 100644
--- a/src/test/js/export.test.js
+++ b/src/test/js/export.test.js
@@ -9,6 +9,7 @@ describe('core', () => {
     assert.equal(typeof core.Address, 'function', 'core.Address')
     assert.equal(typeof core.Address.fromPrefixLen, 'function', 'core.Address.fromPrefixLen')
     assert.equal(typeof core.Address.parseCidr, 'function', 'core.Address.parseCidr')
+    assert.equal(typeof core.Address.strict, 'boolean', 'core.Address.strict')
     assert.equal(typeof core.cidr, 'function', 'core.cidr')
     assert.equal(typeof core.cidrSubnet, 'function', 'core.cidrSubnet')
     assert.equal(typeof core.fromLong, 'function', 'core.fromLong')
@@ -40,6 +41,7 @@ describe('index', () => {
     assert.equal(typeof index.Address, 'function', 'index.Address')
     assert.equal(typeof index.Address.fromPrefixLen, 'function', 'index.Address.fromPrefixLen')
     assert.equal(typeof index.Address.parseCidr, 'function', 'index.Address.parseCidr')
+    assert.equal(typeof index.Address.strict, 'boolean', 'index.Address.strict')
     assert.equal(typeof index.address, 'function', 'index.address')
     assert.equal(typeof index.addresses, 'function', 'index.addresses')
     assert.equal(typeof index.cidr, 'function', 'index.cidr')
diff --git a/src/test/ts/ipv6.test.ts b/src/test/ts/ipv6.test.ts
new file mode 100644
index 0000000..9b038b0
--- /dev/null
+++ b/src/test/ts/ipv6.test.ts
@@ -0,0 +1,610 @@
+/**
+ * This test cases was borrowed and slightly adapted from richb-intermapper/IPv6-Regex.
+ * All credit goes to Rich Brown, Dartware, intermapper.com.
+ *
+ * Source references:
+ *
+ * https://github.com/richb-intermapper/IPv6-Regex/blob/master/test-ipv6-regex.pl
+ *
+ * Original license:
+ *
+ * IPv6 Regex by Dartware, LLC is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License To attribute this work, place a link to http://intermapper.com in the Credits or About... window of your software. We would love to have you send any changes to the code or regular expression back to us at support@intermapper.com.
+ */
+
+import { test, describe, beforeAll, afterAll, expect } from 'vitest'
+import { isV6Format, Address } from '../../main/ts/core.ts'
+
+describe('ipv6', () => {
+  beforeAll(() => Address.strict = false)
+  afterAll(() => Address.strict = true)
+
+  function ipv6test(is: 1 | false, addr: string) {
+    const expected = !!is
+    test(`${addr} should ${expected ? '' : 'not '}be valid`, () => {
+      expect(isV6Format(addr)).toBe(expected)
+    })
+  }
+
+// The test cases...
+  ipv6test(!1,"")// empty string
+  ipv6test(1,"::1")// loopback, compressed, non-routable
+  ipv6test(1,"::")// unspecified, compressed, non-routable
+  ipv6test(1,"0:0:0:0:0:0:0:1")// loopback, full
+  ipv6test(1,"0:0:0:0:0:0:0:0")// unspecified, full
+  ipv6test(1,"2001:DB8:0:0:8:800:200C:417A")// unicast, full
+  ipv6test(1,"FF01:0:0:0:0:0:0:101")// multicast, full
+  ipv6test(1,"2001:DB8::8:800:200C:417A")// unicast, compressed
+  ipv6test(1,"FF01::101")// multicast, compressed
+  ipv6test(!1,"2001:DB8:0:0:8:800:200C:417A:221")// unicast, full
+  ipv6test(!1,"FF01::101::2")// multicast, compressed
+  ipv6test(1,"fe80::217:f2ff:fe07:ed62")
+
+  ipv6test(1,"2001:0000:1234:0000:0000:C1C0:ABCD:0876")
+  ipv6test(1,"3ffe:0b00:0000:0000:0001:0000:0000:000a")
+  ipv6test(1,"FF02:0000:0000:0000:0000:0000:0000:0001")
+  ipv6test(1,"0000:0000:0000:0000:0000:0000:0000:0001")
+  ipv6test(1,"0000:0000:0000:0000:0000:0000:0000:0000")
+  ipv6test(!1,"02001:0000:1234:0000:0000:C1C0:ABCD:0876")	// extra 0 not allowed!
+  ipv6test(!1,"2001:0000:1234:0000:00001:C1C0:ABCD:0876")	// extra 0 not allowed!
+// ipv6test(1," 2001:0000:1234:0000:0000:C1C0:ABCD:0876")		// leading space
+// ipv6test(1,"2001:0000:1234:0000:0000:C1C0:ABCD:0876")		// trailing space
+// ipv6test(1," 2001:0000:1234:0000:0000:C1C0:ABCD:0876  ")	// leading and trailing space
+  ipv6test(!1,"2001:0000:1234:0000:0000:C1C0:ABCD:0876  0")	// junk after valid address
+  ipv6test(!1,"2001:0000:1234: 0000:0000:C1C0:ABCD:0876")	// internal space
+
+  ipv6test(!1,"3ffe:0b00:0000:0001:0000:0000:000a")			// seven segments
+  ipv6test(!1,"FF02:0000:0000:0000:0000:0000:0000:0000:0001")	// nine segments
+  ipv6test(!1,"3ffe:b00::1::a")								// double "::"
+  ipv6test(!1,"::1111:2222:3333:4444:5555:6666::")			// double "::"
+  ipv6test(1,"2::10")
+  ipv6test(1,"ff02::1")
+  ipv6test(1,"fe80::")
+  ipv6test(1,"2002::")
+  ipv6test(1,"2001:db8::")
+  ipv6test(1,"2001:0db8:1234::")
+  ipv6test(1,"::ffff:0:0")
+  ipv6test(1,"::1")
+  ipv6test(1,"1:2:3:4:5:6:7:8")
+  ipv6test(1,"1:2:3:4:5:6::8")
+  ipv6test(1,"1:2:3:4:5::8")
+  ipv6test(1,"1:2:3:4::8")
+  ipv6test(1,"1:2:3::8")
+  ipv6test(1,"1:2::8")
+  ipv6test(1,"1::8")
+  ipv6test(1,"1::2:3:4:5:6:7")
+  ipv6test(1,"1::2:3:4:5:6")
+  ipv6test(1,"1::2:3:4:5")
+  ipv6test(1,"1::2:3:4")
+  ipv6test(1,"1::2:3")
+  ipv6test(1,"1::8")
+  ipv6test(1,"::2:3:4:5:6:7:8")
+  ipv6test(1,"::2:3:4:5:6:7")
+  ipv6test(1,"::2:3:4:5:6")
+  ipv6test(1,"::2:3:4:5")
+  ipv6test(1,"::2:3:4")
+  ipv6test(1,"::2:3")
+  ipv6test(1,"::8")
+  ipv6test(1,"1:2:3:4:5:6::")
+  ipv6test(1,"1:2:3:4:5::")
+  ipv6test(1,"1:2:3:4::")
+  ipv6test(1,"1:2:3::")
+  ipv6test(1,"1:2::")
+  ipv6test(1,"1::")
+  ipv6test(1,"1:2:3:4:5::7:8")
+  ipv6test(!1,"1:2:3::4:5::7:8")							// Double "::"
+  ipv6test(!1,"12345::6:7:8")
+  ipv6test(1,"1:2:3:4::7:8")
+  ipv6test(1,"1:2:3::7:8")
+  ipv6test(1,"1:2::7:8")
+  ipv6test(1,"1::7:8")
+
+// IPv4 addresses as dotted-quads
+  ipv6test(1,"1:2:3:4:5:6:1.2.3.4")
+  ipv6test(1,"1:2:3:4:5::1.2.3.4")
+  ipv6test(1,"1:2:3:4::1.2.3.4")
+  ipv6test(1,"1:2:3::1.2.3.4")
+  ipv6test(1,"1:2::1.2.3.4")
+  ipv6test(1,"1::1.2.3.4")
+  ipv6test(1,"1:2:3:4::5:1.2.3.4")
+  ipv6test(1,"1:2:3::5:1.2.3.4")
+  ipv6test(1,"1:2::5:1.2.3.4")
+  ipv6test(1,"1::5:1.2.3.4")
+  ipv6test(1,"1::5:11.22.33.44")
+  ipv6test(!1,"1::5:400.2.3.4")
+  ipv6test(!1,"1::5:260.2.3.4")
+  ipv6test(!1,"1::5:256.2.3.4")
+  ipv6test(!1,"1::5:1.256.3.4")
+  ipv6test(!1,"1::5:1.2.256.4")
+  ipv6test(!1,"1::5:1.2.3.256")
+  ipv6test(!1,"1::5:300.2.3.4")
+  ipv6test(!1,"1::5:1.300.3.4")
+  ipv6test(!1,"1::5:1.2.300.4")
+  ipv6test(!1,"1::5:1.2.3.300")
+  ipv6test(!1,"1::5:900.2.3.4")
+  ipv6test(!1,"1::5:1.900.3.4")
+  ipv6test(!1,"1::5:1.2.900.4")
+  ipv6test(!1,"1::5:1.2.3.900")
+  ipv6test(!1,"1::5:300.300.300.300")
+  ipv6test(!1,"1::5:3000.30.30.30")
+  ipv6test(!1,"1::400.2.3.4")
+  ipv6test(!1,"1::260.2.3.4")
+  ipv6test(!1,"1::256.2.3.4")
+  ipv6test(!1,"1::1.256.3.4")
+  ipv6test(!1,"1::1.2.256.4")
+  ipv6test(!1,"1::1.2.3.256")
+  ipv6test(!1,"1::300.2.3.4")
+  ipv6test(!1,"1::1.300.3.4")
+  ipv6test(!1,"1::1.2.300.4")
+  ipv6test(!1,"1::1.2.3.300")
+  ipv6test(!1,"1::900.2.3.4")
+  ipv6test(!1,"1::1.900.3.4")
+  ipv6test(!1,"1::1.2.900.4")
+  ipv6test(!1,"1::1.2.3.900")
+  ipv6test(!1,"1::300.300.300.300")
+  ipv6test(!1,"1::3000.30.30.30")
+  ipv6test(!1,"::400.2.3.4")
+  ipv6test(!1,"::260.2.3.4")
+  ipv6test(!1,"::256.2.3.4")
+  ipv6test(!1,"::1.256.3.4")
+  ipv6test(!1,"::1.2.256.4")
+  ipv6test(!1,"::1.2.3.256")
+  ipv6test(!1,"::300.2.3.4")
+  ipv6test(!1,"::1.300.3.4")
+  ipv6test(!1,"::1.2.300.4")
+  ipv6test(!1,"::1.2.3.300")
+  ipv6test(!1,"::900.2.3.4")
+  ipv6test(!1,"::1.900.3.4")
+  ipv6test(!1,"::1.2.900.4")
+  ipv6test(!1,"::1.2.3.900")
+  ipv6test(!1,"::300.300.300.300")
+  ipv6test(!1,"::3000.30.30.30")
+  ipv6test(1,"fe80::217:f2ff:254.7.237.98")
+  ipv6test(1,"::ffff:192.168.1.26")
+  ipv6test(!1,"2001:1:1:1:1:1:255Z255X255Y255")				// garbage instead of "." in IPv4
+  ipv6test(!1,"::ffff:192x168.1.26")							// ditto
+  ipv6test(1,"::ffff:192.168.1.1")
+  ipv6test(1,"0:0:0:0:0:0:13.1.68.3")// IPv4-compatible IPv6 address, full, deprecated
+  ipv6test(1,"0:0:0:0:0:FFFF:129.144.52.38")// IPv4-mapped IPv6 address, full
+  ipv6test(1,"::13.1.68.3")// IPv4-compatible IPv6 address, compressed, deprecated
+  ipv6test(1,"::FFFF:129.144.52.38")// IPv4-mapped IPv6 address, compressed
+  ipv6test(1,"fe80:0:0:0:204:61ff:254.157.241.86")
+  ipv6test(1,"fe80::204:61ff:254.157.241.86")
+  ipv6test(1,"::ffff:12.34.56.78")
+  ipv6test(!1,"::ffff:2.3.4")
+  ipv6test(!1,"::ffff:257.1.2.3")
+  ipv6test(!1,"1.2.3.4")
+
+  ipv6test(!1,"1.2.3.4:1111:2222:3333:4444::5555")  // Aeron
+  ipv6test(!1,"1.2.3.4:1111:2222:3333::5555")
+  ipv6test(!1,"1.2.3.4:1111:2222::5555")
+  ipv6test(!1,"1.2.3.4:1111::5555")
+  ipv6test(!1,"1.2.3.4::5555")
+  ipv6test(!1,"1.2.3.4::")
+
+// Testing IPv4 addresses represented as dotted-quads
+// Leading zero's in IPv4 addresses not allowed: some systems treat the leading "0" in ".086" as the start of an octal number
+// Update: The BNF in RFC-3986 explicitly defines the dec-octet (for IPv4 addresses) not to have a leading zero
+  ipv6test(!1,"fe80:0000:0000:0000:0204:61ff:254.157.241.086")
+  ipv6test(1,"::ffff:192.0.2.128")   // but this is OK, since there's a single digit
+  ipv6test(!1,"XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:00.00.00.00")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:000.000.000.000")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:256.256.256.256")
+
+// Not testing address with subnet mask
+// ipv6test(1,"2001:0DB8:0000:CD30:0000:0000:0000:0000/60")// full, with prefix
+  // ipv6test(1,"2001:0DB8::CD30:0:0:0:0/60")// compressed, with prefix
+  // ipv6test(1,"2001:0DB8:0:CD30::/60")// compressed, with prefix #2
+// ipv6test(1,"::/128")// compressed, unspecified address type, non-routable
+// ipv6test(1,"::1/128")// compressed, loopback address type, non-routable
+// ipv6test(1,"FF00::/8")// compressed, multicast address type
+// ipv6test(1,"FE80::/10")// compressed, link-local unicast, non-routable
+// ipv6test(1,"FEC0::/10")// compressed, site-local unicast, deprecated
+// ipv6test(!1,"124.15.6.89/60")// standard IPv4, prefix not allowed
+
+  ipv6test(1,"fe80:0000:0000:0000:0204:61ff:fe9d:f156")
+  ipv6test(1,"fe80:0:0:0:204:61ff:fe9d:f156")
+  ipv6test(1,"fe80::204:61ff:fe9d:f156")
+  ipv6test(1,"::1")
+  ipv6test(1,"fe80::")
+  ipv6test(1,"fe80::1")
+  ipv6test(!1,":")
+  ipv6test(1,"::ffff:c000:280")
+
+// Aeron supplied these test cases
+  ipv6test(!1,"1111:2222:3333:4444::5555:")
+  ipv6test(!1,"1111:2222:3333::5555:")
+  ipv6test(!1,"1111:2222::5555:")
+  ipv6test(!1,"1111::5555:")
+  ipv6test(!1,"::5555:")
+  ipv6test(!1,":::")
+  ipv6test(!1,"1111:")
+  ipv6test(!1,":")
+
+  ipv6test(!1,":1111:2222:3333:4444::5555")
+  ipv6test(!1,":1111:2222:3333::5555")
+  ipv6test(!1,":1111:2222::5555")
+  ipv6test(!1,":1111::5555")
+  ipv6test(!1,":::5555")
+  ipv6test(!1,":::")
+
+// Additional test cases
+// from http://rt.cpan.org/Public/Bug/Display.html?id=50693
+
+  ipv6test(1,"2001:0db8:85a3:0000:0000:8a2e:0370:7334")
+  ipv6test(1,"2001:db8:85a3:0:0:8a2e:370:7334")
+  ipv6test(1,"2001:db8:85a3::8a2e:370:7334")
+  ipv6test(1,"2001:0db8:0000:0000:0000:0000:1428:57ab")
+  ipv6test(1,"2001:0db8:0000:0000:0000::1428:57ab")
+  ipv6test(1,"2001:0db8:0:0:0:0:1428:57ab")
+  ipv6test(1,"2001:0db8:0:0::1428:57ab")
+  ipv6test(1,"2001:0db8::1428:57ab")
+  ipv6test(1,"2001:db8::1428:57ab")
+  ipv6test(1,"0000:0000:0000:0000:0000:0000:0000:0001")
+  ipv6test(1,"::1")
+  ipv6test(1,"::ffff:0c22:384e")
+  ipv6test(1,"2001:0db8:1234:0000:0000:0000:0000:0000")
+  ipv6test(1,"2001:0db8:1234:ffff:ffff:ffff:ffff:ffff")
+  ipv6test(1,"2001:db8:a::123")
+  ipv6test(1,"fe80::")
+
+  ipv6test(!1,"123")
+  ipv6test(!1,"ldkfj")
+  ipv6test(!1,"2001::FFD3::57ab")
+  ipv6test(!1,"2001:db8:85a3::8a2e:37023:7334")
+  ipv6test(!1,"2001:db8:85a3::8a2e:370k:7334")
+  ipv6test(!1,"1:2:3:4:5:6:7:8:9")
+  ipv6test(!1,"1::2::3")
+  ipv6test(!1,"1:::3:4:5")
+  ipv6test(!1,"1:2:3::4:5:6:7:8:9")
+
+// New from Aeron
+  ipv6test(1,"1111:2222:3333:4444:5555:6666:7777:8888")
+  ipv6test(1,"1111:2222:3333:4444:5555:6666:7777::")
+  ipv6test(1,"1111:2222:3333:4444:5555:6666::")
+  ipv6test(1,"1111:2222:3333:4444:5555::")
+  ipv6test(1,"1111:2222:3333:4444::")
+  ipv6test(1,"1111:2222:3333::")
+  ipv6test(1,"1111:2222::")
+  ipv6test(1,"1111::")
+// ipv6test(1,"::")     #duplicate
+  ipv6test(1,"1111:2222:3333:4444:5555:6666::8888")
+  ipv6test(1,"1111:2222:3333:4444:5555::8888")
+  ipv6test(1,"1111:2222:3333:4444::8888")
+  ipv6test(1,"1111:2222:3333::8888")
+  ipv6test(1,"1111:2222::8888")
+  ipv6test(1,"1111::8888")
+  ipv6test(1,"::8888")
+  ipv6test(1,"1111:2222:3333:4444:5555::7777:8888")
+  ipv6test(1,"1111:2222:3333:4444::7777:8888")
+  ipv6test(1,"1111:2222:3333::7777:8888")
+  ipv6test(1,"1111:2222::7777:8888")
+  ipv6test(1,"1111::7777:8888")
+  ipv6test(1,"::7777:8888")
+  ipv6test(1,"1111:2222:3333:4444::6666:7777:8888")
+  ipv6test(1,"1111:2222:3333::6666:7777:8888")
+  ipv6test(1,"1111:2222::6666:7777:8888")
+  ipv6test(1,"1111::6666:7777:8888")
+  ipv6test(1,"::6666:7777:8888")
+  ipv6test(1,"1111:2222:3333::5555:6666:7777:8888")
+  ipv6test(1,"1111:2222::5555:6666:7777:8888")
+  ipv6test(1,"1111::5555:6666:7777:8888")
+  ipv6test(1,"::5555:6666:7777:8888")
+  ipv6test(1,"1111:2222::4444:5555:6666:7777:8888")
+  ipv6test(1,"1111::4444:5555:6666:7777:8888")
+  ipv6test(1,"::4444:5555:6666:7777:8888")
+  ipv6test(1,"1111::3333:4444:5555:6666:7777:8888")
+  ipv6test(1,"::3333:4444:5555:6666:7777:8888")
+  ipv6test(1,"::2222:3333:4444:5555:6666:7777:8888")
+  ipv6test(1,"1111:2222:3333:4444:5555:6666:123.123.123.123")
+  ipv6test(1,"1111:2222:3333:4444:5555::123.123.123.123")
+  ipv6test(1,"1111:2222:3333:4444::123.123.123.123")
+  ipv6test(1,"1111:2222:3333::123.123.123.123")
+  ipv6test(1,"1111:2222::123.123.123.123")
+  ipv6test(1,"1111::123.123.123.123")
+  ipv6test(1,"::123.123.123.123")
+  ipv6test(1,"1111:2222:3333:4444::6666:123.123.123.123")
+  ipv6test(1,"1111:2222:3333::6666:123.123.123.123")
+  ipv6test(1,"1111:2222::6666:123.123.123.123")
+  ipv6test(1,"1111::6666:123.123.123.123")
+  ipv6test(1,"::6666:123.123.123.123")
+  ipv6test(1,"1111:2222:3333::5555:6666:123.123.123.123")
+  ipv6test(1,"1111:2222::5555:6666:123.123.123.123")
+  ipv6test(1,"1111::5555:6666:123.123.123.123")
+  ipv6test(1,"::5555:6666:123.123.123.123")
+  ipv6test(1,"1111:2222::4444:5555:6666:123.123.123.123")
+  ipv6test(1,"1111::4444:5555:6666:123.123.123.123")
+  ipv6test(1,"::4444:5555:6666:123.123.123.123")
+  ipv6test(1,"1111::3333:4444:5555:6666:123.123.123.123")
+  ipv6test(1,"::2222:3333:4444:5555:6666:123.123.123.123")
+
+// Playing with combinations of "0" and "::"
+// NB: these are all sytactically correct, but are bad form
+//   because "0" adjacent to "::" should be combined into "::"
+  ipv6test(1,"::0:0:0:0:0:0:0")
+  ipv6test(1,"::0:0:0:0:0:0")
+  ipv6test(1,"::0:0:0:0:0")
+  ipv6test(1,"::0:0:0:0")
+  ipv6test(1,"::0:0:0")
+  ipv6test(1,"::0:0")
+  ipv6test(1,"::0")
+  ipv6test(1,"0:0:0:0:0:0:0::")
+  ipv6test(1,"0:0:0:0:0:0::")
+  ipv6test(1,"0:0:0:0:0::")
+  ipv6test(1,"0:0:0:0::")
+  ipv6test(1,"0:0:0::")
+  ipv6test(1,"0:0::")
+  ipv6test(1,"0::")
+
+// New invalid from Aeron
+// Invalid data
+  ipv6test(!1,"XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX")
+
+// Too many components
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:7777:8888:9999")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:7777:8888::")
+  ipv6test(!1,"::2222:3333:4444:5555:6666:7777:8888:9999")
+
+// Too few components
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:7777")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666")
+  ipv6test(!1,"1111:2222:3333:4444:5555")
+  ipv6test(!1,"1111:2222:3333:4444")
+  ipv6test(!1,"1111:2222:3333")
+  ipv6test(!1,"1111:2222")
+  ipv6test(!1,"1111")
+
+// Missing :
+  ipv6test(!1,"11112222:3333:4444:5555:6666:7777:8888")
+  ipv6test(!1,"1111:22223333:4444:5555:6666:7777:8888")
+  ipv6test(!1,"1111:2222:33334444:5555:6666:7777:8888")
+  ipv6test(!1,"1111:2222:3333:44445555:6666:7777:8888")
+  ipv6test(!1,"1111:2222:3333:4444:55556666:7777:8888")
+  ipv6test(!1,"1111:2222:3333:4444:5555:66667777:8888")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:77778888")
+
+// Missing : intended for ::
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:7777:8888:")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:7777:")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:")
+  ipv6test(!1,"1111:2222:3333:4444:5555:")
+  ipv6test(!1,"1111:2222:3333:4444:")
+  ipv6test(!1,"1111:2222:3333:")
+  ipv6test(!1,"1111:2222:")
+  ipv6test(!1,"1111:")
+  ipv6test(!1,":")
+  ipv6test(!1,":8888")
+  ipv6test(!1,":7777:8888")
+  ipv6test(!1,":6666:7777:8888")
+  ipv6test(!1,":5555:6666:7777:8888")
+  ipv6test(!1,":4444:5555:6666:7777:8888")
+  ipv6test(!1,":3333:4444:5555:6666:7777:8888")
+  ipv6test(!1,":2222:3333:4444:5555:6666:7777:8888")
+  ipv6test(!1,":1111:2222:3333:4444:5555:6666:7777:8888")
+
+// :::
+  ipv6test(!1,":::2222:3333:4444:5555:6666:7777:8888")
+  ipv6test(!1,"1111:::3333:4444:5555:6666:7777:8888")
+  ipv6test(!1,"1111:2222:::4444:5555:6666:7777:8888")
+  ipv6test(!1,"1111:2222:3333:::5555:6666:7777:8888")
+  ipv6test(!1,"1111:2222:3333:4444:::6666:7777:8888")
+  ipv6test(!1,"1111:2222:3333:4444:5555:::7777:8888")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:::8888")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:7777:::")
+
+// Double ::")
+  ipv6test(!1,"::2222::4444:5555:6666:7777:8888")
+  ipv6test(!1,"::2222:3333::5555:6666:7777:8888")
+  ipv6test(!1,"::2222:3333:4444::6666:7777:8888")
+  ipv6test(!1,"::2222:3333:4444:5555::7777:8888")
+  ipv6test(!1,"::2222:3333:4444:5555:7777::8888")
+  ipv6test(!1,"::2222:3333:4444:5555:7777:8888::")
+
+  ipv6test(!1,"1111::3333::5555:6666:7777:8888")
+  ipv6test(!1,"1111::3333:4444::6666:7777:8888")
+  ipv6test(!1,"1111::3333:4444:5555::7777:8888")
+  ipv6test(!1,"1111::3333:4444:5555:6666::8888")
+  ipv6test(!1,"1111::3333:4444:5555:6666:7777::")
+
+  ipv6test(!1,"1111:2222::4444::6666:7777:8888")
+  ipv6test(!1,"1111:2222::4444:5555::7777:8888")
+  ipv6test(!1,"1111:2222::4444:5555:6666::8888")
+  ipv6test(!1,"1111:2222::4444:5555:6666:7777::")
+
+  ipv6test(!1,"1111:2222:3333::5555::7777:8888")
+  ipv6test(!1,"1111:2222:3333::5555:6666::8888")
+  ipv6test(!1,"1111:2222:3333::5555:6666:7777::")
+
+  ipv6test(!1,"1111:2222:3333:4444::6666::8888")
+  ipv6test(!1,"1111:2222:3333:4444::6666:7777::")
+
+  ipv6test(!1,"1111:2222:3333:4444:5555::7777::")
+
+
+// Too many components"
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:7777:8888:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:7777:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666::1.2.3.4")
+  ipv6test(!1,"::2222:3333:4444:5555:6666:7777:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:1.2.3.4.5")
+
+// Too few components
+  ipv6test(!1,"1111:2222:3333:4444:5555:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:4444:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:1.2.3.4")
+  ipv6test(!1,"1111:2222:1.2.3.4")
+  ipv6test(!1,"1111:1.2.3.4")
+  ipv6test(!1,"1.2.3.4")
+
+// Missing :
+  ipv6test(!1,"11112222:3333:4444:5555:6666:1.2.3.4")
+  ipv6test(!1,"1111:22223333:4444:5555:6666:1.2.3.4")
+  ipv6test(!1,"1111:2222:33334444:5555:6666:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:44445555:6666:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:4444:55556666:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:4444:5555:66661.2.3.4")
+
+// Missing .
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:255255.255.255")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:255.255255.255")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:255.255.255255")
+
+// Missing : intended for ::
+  ipv6test(!1,":1.2.3.4")
+  ipv6test(!1,":6666:1.2.3.4")
+  ipv6test(!1,":5555:6666:1.2.3.4")
+  ipv6test(!1,":4444:5555:6666:1.2.3.4")
+  ipv6test(!1,":3333:4444:5555:6666:1.2.3.4")
+  ipv6test(!1,":2222:3333:4444:5555:6666:1.2.3.4")
+  ipv6test(!1,":1111:2222:3333:4444:5555:6666:1.2.3.4")
+
+// :::
+  ipv6test(!1,":::2222:3333:4444:5555:6666:1.2.3.4")
+  ipv6test(!1,"1111:::3333:4444:5555:6666:1.2.3.4")
+  ipv6test(!1,"1111:2222:::4444:5555:6666:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:::5555:6666:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:4444:::6666:1.2.3.4")
+  ipv6test(!1,"1111:2222:3333:4444:5555:::1.2.3.4")
+
+// Double ::
+  ipv6test(!1,"::2222::4444:5555:6666:1.2.3.4")
+  ipv6test(!1,"::2222:3333::5555:6666:1.2.3.4")
+  ipv6test(!1,"::2222:3333:4444::6666:1.2.3.4")
+  ipv6test(!1,"::2222:3333:4444:5555::1.2.3.4")
+
+  ipv6test(!1,"1111::3333::5555:6666:1.2.3.4")
+  ipv6test(!1,"1111::3333:4444::6666:1.2.3.4")
+  ipv6test(!1,"1111::3333:4444:5555::1.2.3.4")
+
+  ipv6test(!1,"1111:2222::4444::6666:1.2.3.4")
+  ipv6test(!1,"1111:2222::4444:5555::1.2.3.4")
+
+  ipv6test(!1,"1111:2222:3333::5555::1.2.3.4")
+
+// Missing parts
+  ipv6test(!1,"::.")
+  ipv6test(!1,"::..")
+  ipv6test(!1,"::...")
+  ipv6test(!1,"::1...")
+  ipv6test(!1,"::1.2..")
+  ipv6test(!1,"::1.2.3.")
+  ipv6test(!1,"::.2..")
+  ipv6test(!1,"::.2.3.")
+  ipv6test(!1,"::.2.3.4")
+  ipv6test(!1,"::..3.")
+  ipv6test(!1,"::..3.4")
+  ipv6test(!1,"::...4")
+
+// Extra : in front
+  ipv6test(!1,":1111:2222:3333:4444:5555:6666:7777::")
+  ipv6test(!1,":1111:2222:3333:4444:5555:6666::")
+  ipv6test(!1,":1111:2222:3333:4444:5555::")
+  ipv6test(!1,":1111:2222:3333:4444::")
+  ipv6test(!1,":1111:2222:3333::")
+  ipv6test(!1,":1111:2222::")
+  ipv6test(!1,":1111::")
+  ipv6test(!1,":::")
+  ipv6test(!1,":1111:2222:3333:4444:5555:6666::8888")
+  ipv6test(!1,":1111:2222:3333:4444:5555::8888")
+  ipv6test(!1,":1111:2222:3333:4444::8888")
+  ipv6test(!1,":1111:2222:3333::8888")
+  ipv6test(!1,":1111:2222::8888")
+  ipv6test(!1,":1111::8888")
+  ipv6test(!1,":::8888")
+  ipv6test(!1,":1111:2222:3333:4444:5555::7777:8888")
+  ipv6test(!1,":1111:2222:3333:4444::7777:8888")
+  ipv6test(!1,":1111:2222:3333::7777:8888")
+  ipv6test(!1,":1111:2222::7777:8888")
+  ipv6test(!1,":1111::7777:8888")
+  ipv6test(!1,":::7777:8888")
+  ipv6test(!1,":1111:2222:3333:4444::6666:7777:8888")
+  ipv6test(!1,":1111:2222:3333::6666:7777:8888")
+  ipv6test(!1,":1111:2222::6666:7777:8888")
+  ipv6test(!1,":1111::6666:7777:8888")
+  ipv6test(!1,":::6666:7777:8888")
+  ipv6test(!1,":1111:2222:3333::5555:6666:7777:8888")
+  ipv6test(!1,":1111:2222::5555:6666:7777:8888")
+  ipv6test(!1,":1111::5555:6666:7777:8888")
+  ipv6test(!1,":::5555:6666:7777:8888")
+  ipv6test(!1,":1111:2222::4444:5555:6666:7777:8888")
+  ipv6test(!1,":1111::4444:5555:6666:7777:8888")
+  ipv6test(!1,":::4444:5555:6666:7777:8888")
+  ipv6test(!1,":1111::3333:4444:5555:6666:7777:8888")
+  ipv6test(!1,":::3333:4444:5555:6666:7777:8888")
+  ipv6test(!1,":::2222:3333:4444:5555:6666:7777:8888")
+  ipv6test(!1,":1111:2222:3333:4444:5555:6666:1.2.3.4")
+  ipv6test(!1,":1111:2222:3333:4444:5555::1.2.3.4")
+  ipv6test(!1,":1111:2222:3333:4444::1.2.3.4")
+  ipv6test(!1,":1111:2222:3333::1.2.3.4")
+  ipv6test(!1,":1111:2222::1.2.3.4")
+  ipv6test(!1,":1111::1.2.3.4")
+  ipv6test(!1,":::1.2.3.4")
+  ipv6test(!1,":1111:2222:3333:4444::6666:1.2.3.4")
+  ipv6test(!1,":1111:2222:3333::6666:1.2.3.4")
+  ipv6test(!1,":1111:2222::6666:1.2.3.4")
+  ipv6test(!1,":1111::6666:1.2.3.4")
+  ipv6test(!1,":::6666:1.2.3.4")
+  ipv6test(!1,":1111:2222:3333::5555:6666:1.2.3.4")
+  ipv6test(!1,":1111:2222::5555:6666:1.2.3.4")
+  ipv6test(!1,":1111::5555:6666:1.2.3.4")
+  ipv6test(!1,":::5555:6666:1.2.3.4")
+  ipv6test(!1,":1111:2222::4444:5555:6666:1.2.3.4")
+  ipv6test(!1,":1111::4444:5555:6666:1.2.3.4")
+  ipv6test(!1,":::4444:5555:6666:1.2.3.4")
+  ipv6test(!1,":1111::3333:4444:5555:6666:1.2.3.4")
+  ipv6test(!1,":::2222:3333:4444:5555:6666:1.2.3.4")
+
+// Extra : at end
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:7777:::")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666:::")
+  ipv6test(!1,"1111:2222:3333:4444:5555:::")
+  ipv6test(!1,"1111:2222:3333:4444:::")
+  ipv6test(!1,"1111:2222:3333:::")
+  ipv6test(!1,"1111:2222:::")
+  ipv6test(!1,"1111:::")
+  ipv6test(!1,":::")
+  ipv6test(!1,"1111:2222:3333:4444:5555:6666::8888:")
+  ipv6test(!1,"1111:2222:3333:4444:5555::8888:")
+  ipv6test(!1,"1111:2222:3333:4444::8888:")
+  ipv6test(!1,"1111:2222:3333::8888:")
+  ipv6test(!1,"1111:2222::8888:")
+  ipv6test(!1,"1111::8888:")
+  ipv6test(!1,"::8888:")
+  ipv6test(!1,"1111:2222:3333:4444:5555::7777:8888:")
+  ipv6test(!1,"1111:2222:3333:4444::7777:8888:")
+  ipv6test(!1,"1111:2222:3333::7777:8888:")
+  ipv6test(!1,"1111:2222::7777:8888:")
+  ipv6test(!1,"1111::7777:8888:")
+  ipv6test(!1,"::7777:8888:")
+  ipv6test(!1,"1111:2222:3333:4444::6666:7777:8888:")
+  ipv6test(!1,"1111:2222:3333::6666:7777:8888:")
+  ipv6test(!1,"1111:2222::6666:7777:8888:")
+  ipv6test(!1,"1111::6666:7777:8888:")
+  ipv6test(!1,"::6666:7777:8888:")
+  ipv6test(!1,"1111:2222:3333::5555:6666:7777:8888:")
+  ipv6test(!1,"1111:2222::5555:6666:7777:8888:")
+  ipv6test(!1,"1111::5555:6666:7777:8888:")
+  ipv6test(!1,"::5555:6666:7777:8888:")
+  ipv6test(!1,"1111:2222::4444:5555:6666:7777:8888:")
+  ipv6test(!1,"1111::4444:5555:6666:7777:8888:")
+  ipv6test(!1,"::4444:5555:6666:7777:8888:")
+  ipv6test(!1,"1111::3333:4444:5555:6666:7777:8888:")
+  ipv6test(!1,"::3333:4444:5555:6666:7777:8888:")
+  ipv6test(!1,"::2222:3333:4444:5555:6666:7777:8888:")
+
+// Additional cases: http://crisp.tweakblogs.net/blog/2031/ipv6-validation-%28and-caveats%29.html
+  ipv6test(1,"0:a:b:c:d:e:f::")
+  ipv6test(1,"::0:a:b:c:d:e:f") // syntactically correct, but bad form (::0:... could be combined)
+  ipv6test(1,"a:b:c:d:e:f:0::")
+  ipv6test(!1,"':10.0.0.1")
+
+// Testing for IPv4 in IPv6 format:
+  ipv6test(1,"::10.0.0.1")
+  ipv6test(1,"::FFFF:10.0.0.1")
+// NB All the regexes fail to detect somewhat suspect v4 in v6 addresses
+// Leaving this test out
+// ipv6test(!1,"1::1.2.3.4")
+
+// Testing for "%" at end of IPv6 address
+  ipv6test(!1,"2001:db8::%1")
+})
diff --git a/target/cjs/core.cjs b/target/cjs/core.cjs
index e659900..b17881c 100644
--- a/target/cjs/core.cjs
+++ b/target/cjs/core.cjs
@@ -338,13 +338,13 @@ var _Address = class _Address {
     if (!addr) throw new Error(`Invalid address: empty`);
     if (addr === "::") return this.create(/* @__PURE__ */ BigInt("0"), 6, addr);
     if (addr === "0") return this.create(/* @__PURE__ */ BigInt("0"), 4, addr);
-    return addr.includes(":") ? this.fromIPv6(addr) : this.fromIPv4(addr);
+    return addr.includes(":") ? this.fromIPv6(addr, this.strict) : this.fromIPv4(addr);
   }
-  static fromIPv6(addr) {
+  static fromIPv6(addr, strict) {
     const al = addr.length;
     const sep = addr.indexOf("::");
     if (al > IPV6_LEN_LIM || sep !== -1 && addr.indexOf("::", sep + 1) !== -1)
-      throw new Error(`Invalid address: ${addr}`);
+      throw new Error(`Invalid address0: ${addr}`);
     const groups = [];
     let p = 0, gc = -1;
     while (true) {
@@ -357,7 +357,10 @@ var _Address = class _Address {
           throw new Error(`Invalid address: ${addr}`);
         gc = groups.length;
       } else if (last && v.includes(".")) {
-        if (groups.length > 6 || gc === groups.length || gc === -1 && groups.length !== 6 || groups[groups.length - 1] !== 65535 || groups.slice(0, -1).some((x) => x !== 0)) throw new Error(`Invalid address: ${addr}`);
+        if (gc === -1 ? groups.length !== 6 : groups.length > 5)
+          throw new Error(`Invalid address: ${addr}`);
+        if (strict && (gc === groups.length || groups[groups.length - 1] !== 65535 || groups.slice(0, -1).some((x) => x !== 0)))
+          throw new Error(`Invalid address: ${addr}`);
         const long = _Address.normalizeToLong(v, true);
         if (long === -1) throw new Error(`Invalid address: ${addr}`);
         return this.create(/* @__PURE__ */ BigInt("0xffff") << /* @__PURE__ */ BigInt("32") | BigInt(long), 6, addr);
@@ -369,7 +372,7 @@ var _Address = class _Address {
       p = i + 1;
     }
     const offset = 8 - groups.length;
-    if (gc === -1 ? offset !== 0 : offset < 1) throw new Error(`Invalid address: ${addr}`);
+    if (gc === -1 ? offset !== 0 : offset < 1) throw new Error(`Invalid address4: ${addr}`);
     let big = /* @__PURE__ */ BigInt("0");
     for (let i = 0; i < 8; i++) {
       const idx = i < gc ? i : i < gc + offset ? -1 : i - offset;
@@ -440,6 +443,7 @@ var _Address = class _Address {
     return !this.isPrivate(addr);
   }
 };
+__publicField(_Address, "strict", true);
 __publicField(_Address, "fromPrefixLen", (prefixlen, family) => {
   if (typeof prefixlen === "string" && !isDec(prefixlen)) throw new Error(`Invalid prefix: ${prefixlen}`);
   const len = +prefixlen | 0;
diff --git a/target/dts/core.d.ts b/target/dts/core.d.ts
index 4146a58..b09a240 100644
--- a/target/dts/core.d.ts
+++ b/target/dts/core.d.ts
@@ -26,6 +26,7 @@ export declare class Address {
     toLong(): number;
     get range(): Special | undefined;
     private static create;
+    static strict: boolean;
     static from(raw: Raw): Address;
     static mask(addr: Raw, mask: Raw): string;
     static subnet(addr: Raw, smask: Raw): Subnet;
diff --git a/target/esm/core.mjs b/target/esm/core.mjs
index 555bad1..f937557 100644
--- a/target/esm/core.mjs
+++ b/target/esm/core.mjs
@@ -303,13 +303,13 @@ var _Address = class _Address {
     if (!addr) throw new Error(`Invalid address: empty`);
     if (addr === "::") return this.create(/* @__PURE__ */ BigInt("0"), 6, addr);
     if (addr === "0") return this.create(/* @__PURE__ */ BigInt("0"), 4, addr);
-    return addr.includes(":") ? this.fromIPv6(addr) : this.fromIPv4(addr);
+    return addr.includes(":") ? this.fromIPv6(addr, this.strict) : this.fromIPv4(addr);
   }
-  static fromIPv6(addr) {
+  static fromIPv6(addr, strict) {
     const al = addr.length;
     const sep = addr.indexOf("::");
     if (al > IPV6_LEN_LIM || sep !== -1 && addr.indexOf("::", sep + 1) !== -1)
-      throw new Error(`Invalid address: ${addr}`);
+      throw new Error(`Invalid address0: ${addr}`);
     const groups = [];
     let p = 0, gc = -1;
     while (true) {
@@ -322,7 +322,10 @@ var _Address = class _Address {
           throw new Error(`Invalid address: ${addr}`);
         gc = groups.length;
       } else if (last && v.includes(".")) {
-        if (groups.length > 6 || gc === groups.length || gc === -1 && groups.length !== 6 || groups[groups.length - 1] !== 65535 || groups.slice(0, -1).some((x) => x !== 0)) throw new Error(`Invalid address: ${addr}`);
+        if (gc === -1 ? groups.length !== 6 : groups.length > 5)
+          throw new Error(`Invalid address: ${addr}`);
+        if (strict && (gc === groups.length || groups[groups.length - 1] !== 65535 || groups.slice(0, -1).some((x) => x !== 0)))
+          throw new Error(`Invalid address: ${addr}`);
         const long = _Address.normalizeToLong(v, true);
         if (long === -1) throw new Error(`Invalid address: ${addr}`);
         return this.create(/* @__PURE__ */ BigInt("0xffff") << /* @__PURE__ */ BigInt("32") | BigInt(long), 6, addr);
@@ -334,7 +337,7 @@ var _Address = class _Address {
       p = i + 1;
     }
     const offset = 8 - groups.length;
-    if (gc === -1 ? offset !== 0 : offset < 1) throw new Error(`Invalid address: ${addr}`);
+    if (gc === -1 ? offset !== 0 : offset < 1) throw new Error(`Invalid address4: ${addr}`);
     let big = /* @__PURE__ */ BigInt("0");
     for (let i = 0; i < 8; i++) {
       const idx = i < gc ? i : i < gc + offset ? -1 : i - offset;
@@ -405,6 +408,7 @@ var _Address = class _Address {
     return !this.isPrivate(addr);
   }
 };
+__publicField(_Address, "strict", true);
 __publicField(_Address, "fromPrefixLen", (prefixlen, family) => {
   if (typeof prefixlen === "string" && !isDec(prefixlen)) throw new Error(`Invalid prefix: ${prefixlen}`);
   const len = +prefixlen | 0;