diff --git a/src/socket/address.cr b/src/socket/address.cr
index 0670bc25a074..9c1993d1190e 100644
--- a/src/socket/address.cr
+++ b/src/socket/address.cr
@@ -228,8 +228,9 @@ class Socket
         addr.s_addr & 0x000000ff_u32 == 0x0000007f_u32
       in LibC::In6Addr
         addr8 = ipv6_addr8(addr)
-        addr8 == StaticArray[0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 1_u8] ||             # "::1"
-          addr8.to_slice[0, 13] == StaticArray[0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 255_u8, 255_u8, 127_u8].to_slice # "::ffff:127.0.0.1/104"
+        num = addr8.unsafe_as(UInt128)
+        num == (1_u128 << 120) ||                                                      # "::1"
+          num & 0xffffffffffffffffffffffffff_u128 == 0x7fffff00000000000000000000_u128 # "::ffff:127.0.0.1/104"
       end
     end