From 3f4f825ec14c45dd149a743eb80e98e7bb5e9ec5 Mon Sep 17 00:00:00 2001
From: Viktor Liu <17948409+lixmal@users.noreply.github.com>
Date: Fri, 5 Dec 2025 17:42:49 +0100
Subject: [PATCH] [client] Fix DNS forwarder returning broken records on 4 to 6
 mapped IP addresses (#4887)

---
 client/internal/dnsfwd/forwarder.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/client/internal/dnsfwd/forwarder.go b/client/internal/dnsfwd/forwarder.go
index aef16a8cf..6b8042ccb 100644
--- a/client/internal/dnsfwd/forwarder.go
+++ b/client/internal/dnsfwd/forwarder.go
@@ -234,6 +234,11 @@ func (f *DNSForwarder) handleDNSQuery(w dns.ResponseWriter, query *dns.Msg) *dns
 		return nil
 	}
 
+	// Unmap IPv4-mapped IPv6 addresses that some resolvers may return
+	for i, ip := range ips {
+		ips[i] = ip.Unmap()
+	}
+
 	f.updateInternalState(ips, mostSpecificResId, matchingEntries)
 	f.addIPsToResponse(resp, domain, ips)
 	f.cache.set(domain, question.Qtype, ips)