# Functions for working with IP addresses ## IPv4NumToString(num) Takes a UInt32 number. Interprets it as an IPv4 address in big endian. Returns a string containing the corresponding IPv4 address in the format A.B.C.d (dot-separated numbers in decimal form). ## IPv4StringToNum(s) The reverse function of IPv4NumToString. If the IPv4 address has an invalid format, it returns 0. ## IPv4NumToStringClassC(num) Similar to IPv4NumToString, but using xxx instead of the last octet. Example: ``` sql SELECT IPv4NumToStringClassC(ClientIP) AS k, count() AS c FROM test.hits GROUP BY k ORDER BY c DESC LIMIT 10 ``` ``` ┌─k──────────────┬─────c─┐ │ 83.149.9.xxx │ 26238 │ │ 217.118.81.xxx │ 26074 │ │ 213.87.129.xxx │ 25481 │ │ 83.149.8.xxx │ 24984 │ │ 217.118.83.xxx │ 22797 │ │ 78.25.120.xxx │ 22354 │ │ 213.87.131.xxx │ 21285 │ │ 78.25.121.xxx │ 20887 │ │ 188.162.65.xxx │ 19694 │ │ 83.149.48.xxx │ 17406 │ └────────────────┴───────┘ ``` Since using 'xxx' is highly unusual, this may be changed in the future. We recommend that you don't rely on the exact format of this fragment. ### IPv6NumToString(x) Accepts a FixedString(16) value containing the IPv6 address in binary format. Returns a string containing this address in text format. IPv6-mapped IPv4 addresses are output in the format ::ffff:111.222.33.44. Examples: ``` sql SELECT IPv6NumToString(toFixedString(unhex('2A0206B8000000000000000000000011'), 16)) AS addr ``` ``` ┌─addr─────────┐ │ 2a02:6b8::11 │ └──────────────┘ ``` ``` sql SELECT IPv6NumToString(ClientIP6 AS k), count() AS c FROM hits_all WHERE EventDate = today() AND substring(ClientIP6, 1, 12) != unhex('00000000000000000000FFFF') GROUP BY k ORDER BY c DESC LIMIT 10 ``` ``` ┌─IPv6NumToString(ClientIP6)──────────────┬─────c─┐ │ 2a02:2168:aaa:bbbb::2 │ 24695 │ │ 2a02:2698:abcd:abcd:abcd:abcd:8888:5555 │ 22408 │ │ 2a02:6b8:0:fff::ff │ 16389 │ │ 2a01:4f8:111:6666::2 │ 16016 │ │ 2a02:2168:888:222::1 │ 15896 │ │ 2a01:7e00::ffff:ffff:ffff:222 │ 14774 │ │ 2a02:8109:eee:ee:eeee:eeee:eeee:eeee │ 14443 │ │ 2a02:810b:8888:888:8888:8888:8888:8888 │ 14345 │ │ 2a02:6b8:0:444:4444:4444:4444:4444 │ 14279 │ │ 2a01:7e00::ffff:ffff:ffff:ffff │ 13880 │ └─────────────────────────────────────────┴───────┘ ``` ``` sql SELECT IPv6NumToString(ClientIP6 AS k), count() AS c FROM hits_all WHERE EventDate = today() GROUP BY k ORDER BY c DESC LIMIT 10 ``` ``` ┌─IPv6NumToString(ClientIP6)─┬──────c─┐ │ ::ffff:94.26.111.111 │ 747440 │ │ ::ffff:37.143.222.4 │ 529483 │ │ ::ffff:5.166.111.99 │ 317707 │ │ ::ffff:46.38.11.77 │ 263086 │ │ ::ffff:79.105.111.111 │ 186611 │ │ ::ffff:93.92.111.88 │ 176773 │ │ ::ffff:84.53.111.33 │ 158709 │ │ ::ffff:217.118.11.22 │ 154004 │ │ ::ffff:217.118.11.33 │ 148449 │ │ ::ffff:217.118.11.44 │ 148243 │ └────────────────────────────┴────────┘ ``` ## IPv6StringToNum(s) The reverse function of IPv6NumToString. If the IPv6 address has an invalid format, it returns a string of null bytes. HEX can be uppercase or lowercase. ## IPv4ToIPv6(x) Takes a UInt32 number. Interprets it as an IPv4 address in big endian. Returns a FixedString(16) value containing the IPv6 address in binary format. Examples: ``` sql SELECT IPv6NumToString(IPv4ToIPv6(IPv4StringToNum('192.168.0.1'))) AS addr ``` ``` ┌─addr───────────────┐ │ ::ffff:192.168.0.1 │ └────────────────────┘ ``` ## cutIPv6(x, bitsToCutForIPv6, bitsToCutForIPv4) Accepts a FixedString(16) value containing the IPv6 address in binary format. Returns a string containing the address of the specified number of bits removed in text format. For example: ```sql WITH IPv6StringToNum('2001:0DB8:AC10:FE01:FEED:BABE:CAFE:F00D') AS ipv6, IPv4ToIPv6(IPv4StringToNum('192.168.0.1')) AS ipv4 SELECT cutIPv6(ipv6, 2, 0), cutIPv6(ipv4, 0, 2) ``` ``` ┌─cutIPv6(ipv6, 2, 0)─────────────────┬─cutIPv6(ipv4, 0, 2)─┐ │ 2001:db8:ac10:fe01:feed:babe:cafe:0 │ ::ffff:192.168.0.0 │ └─────────────────────────────────────┴─────────────────────┘ ``` [Original article](https://clickhouse.yandex/docs/en/query_language/functions/ip_address_functions/)