From 983dc14f2c52741ee22e04e8b379d38153fb989e Mon Sep 17 00:00:00 2001
From: "Roger A. Light" <roger@atchoo.org>
Date: Sat, 3 Apr 2021 11:33:57 +0100
Subject: [PATCH] Provide help for users trying to bind to privileged ports.

Closes #2098.
---
 src/net.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/net.c b/src/net.c
index cbcfc677d0..74fdebae31 100644
--- a/src/net.c
+++ b/src/net.c
@@ -754,6 +754,12 @@ static int net__socket_listen_tcp(struct mosquitto__listener *listener)
 #endif
 
 		if(bind(sock, rp->ai_addr, rp->ai_addrlen) == -1){
+#if defined(__linux__)
+			if(errno == EACCES){
+				log__printf(NULL, MOSQ_LOG_ERR, "If you are trying to bind to a privileged port (<1024), try using setcap and do not start the broker as root:");
+				log__printf(NULL, MOSQ_LOG_ERR, "    sudo setcap 'CAP_NET_BIND_SERVICE=+ep /usr/sbin/mosquitto'");
+			}
+#endif
 			net__print_error(MOSQ_LOG_ERR, "Error: %s");
 			COMPAT_CLOSE(sock);
 			freeaddrinfo(ainfo);