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reverse_ip

local reversed = kumo.dns.reverse_ip(IP)
Since: Version 2025.12.02-67ee9e96

The functionality described in this section requires version 2025.12.02-67ee9e96 of KumoMTA, or a more recent version.

Given an IP address in either V4 or V6 format as the input, returns the reversed address.

This function is purely local string manipulation; no actual DNS queries are performed.

print(kumo.dns.reverse_ip '127.0.0.1')
-- prints out:
-- 1.0.0.127

print(kumo.dns.reverse_ip '::1')
-- prints out:
-- 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0