From 20ee48a7eb3c52034983eed5bfb1836e2e38efde Mon Sep 17 00:00:00 2001
From: Chris <103056583+gritsly@users.noreply.github.com>
Date: Wed, 3 Dec 2025 09:58:45 +0000
Subject: [PATCH] disable multicast loopback on the send socket

---
 proxy/src/forwarder.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/proxy/src/forwarder.rs b/proxy/src/forwarder.rs
index aa897255..6ffe4024 100644
--- a/proxy/src/forwarder.rs
+++ b/proxy/src/forwarder.rs
@@ -326,6 +326,8 @@ pub fn start_multicast_forwarder_thread(
                     match try_create_ipv6_socket(ipv6_addr) {
                         Ok(socket) => {
                             info!("Successfully bound send socket to IPv6 dual-stack address.");
+                            socket.set_multicast_loop_v6(false)
+                              .expect("Failed to disable IPv6 multicast loopback");
                             socket
                         }
                         Err(e) if e.raw_os_error() == Some(libc::EAFNOSUPPORT) => {
@@ -335,6 +337,8 @@ pub fn start_multicast_forwarder_thread(
                             let socket = UdpSocket::bind(ipv4_addr)
                                 .expect("Failed to bind to IPv4 socket after IPv6 failed");
                             socket.set_multicast_ttl_v4(IP_MULTICAST_TTL).expect("IP_MULTICAST_TTL_V4");
+                            socket.set_multicast_loop_v4(false)
+                                .expect("Failed to disable IPv4 multicast loopback");
                             socket
                         }
                         Err(e) => {