--- src/server.c
+++ src/server.c
@@ -292,12 +292,14 @@
 			Log_fatal("bind %s %d: %s", addressString, Util_addressToPort(addresses[1]), strerror(errno));
 			free(addressString);
 		}
+#if defined(IPV6_TCLASS)
 		val = 0xe0;
 		if (setsockopt(sockets[1], IPPROTO_IPV6, IPV6_TCLASS, &val, sizeof(val)) < 0)
 			Log_warn("Server: Failed to set TOS for UDP Socket");
 		val = 0x80;
 		if (setsockopt(sockets[1], IPPROTO_IPV6, IPV6_TCLASS, &val, sizeof(val)) < 0)
 			Log_warn("Server: Failed to set TOS for UDP Socket");
+#endif
 
 		fcntl(sockets[1], F_SETFL, O_NONBLOCK);
 		pollfds[(hasv4) ? 3 : 1].fd = sockets[1];