How can I check if an ipaddress is part of a subnet, given ipaddress can be ipv4 or ipv6?

I currently have it working for ipv4 only:

set @ip = '';
set @subnet = '';
set @xor_bw_ip_n_subnet = inet_aton(@ip) ^ inet_aton(substring_index(@subnet, '/', 1));
select ((@xor_bw_ip_n_subnet) >> 32-substring_index(@subnet,'/',-1)) = 0;   -- if ip in subnet, then should be 0

For ipv6, how can I use inet6_ntoa/inet6_aton to check if IPaddress is part of a subnet (basically trying to do bitwise operation on ipv6 address)?

I am using mysql v5.6.19


  • Recommend you do this processing in a programming language, not SQL.
    – Rick James
    Commented Jun 22, 2015 at 23:18
  • It makes it really slow if I do it in a programming language, since... I have close to a million subnets to be searched within
    – amulllb
    Commented Jun 23, 2015 at 4:10
  • Are you comparing 1 IP address to a million subnets? Do your subnets overlap?
    – Rick James
    Commented Jun 23, 2015 at 5:30
  • yes. I am comparing 1 ip address to a million subnets. the query perfectly works for ipv4 and is really quick. without this query, from python, its really slow. thats why i wish to do similarly for ipv6
    – amulllb
    Commented Jun 23, 2015 at 5:45

1 Answer 1


I assume your IPv6 is in BINARY(16)? Build a 128-row table of the BINARY(16) values for the subnet masks. (/128 is all 1's.) JOIN to the table and do masking on each half of the address --

WHERE (LEFT(ip, 8)  & LEFT(mask, 8))  == LEFT(ip, 8)
  AND (RIGHT(ip, 8) & RIGHT(mask, 8)) == RIGHT(ip, 8)

(No shifting.)

  • yes, i am actually storing all the ipaddresses in a table with columns: ipaddr (as varbinary(16)), ipprefixlength (as integer). this table stores ipv4 and ipv6 both addresses which needs to be searched against a ipaddr
    – amulllb
    Commented Jun 23, 2015 at 7:05
  • i am not that good at mysql, can you please provide an example?
    – amulllb
    Commented Jun 23, 2015 at 7:06
  • sorry, but dont LEFT and RIGHT only work on string?
    – amulllb
    Commented Jun 23, 2015 at 7:10
  • never mind, i solved it using javascript/node.js ip-addr programmatic approach... its decently fast
    – amulllb
    Commented Jun 23, 2015 at 8:54

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