--- src/common.c	2026-07-04 18:51:28.000000000 +0800
+++ src/common.c	2026-07-17 17:27:38.000000000 +0800
@@ -657,8 +657,10 @@
 	    if(!idx || (*SAFAMILY(&param->sinsl) == AF_INET && param->srv->so._setsockopt(param->sostate, param->remsock, IPPROTO_IP, IP_BOUND_IF, &idx, sizeof(idx))))
 			return 12;
 #ifndef NOIPV6
+#ifdef IPV6_BOUND_IF
 	    if(*SAFAMILY(&param->sinsl) == AF_INET6 && param->srv->so._setsockopt(param->sostate, param->remsock, IPPROTO_IPV6, IPV6_BOUND_IF, &idx, sizeof(idx))) return 12;
 #endif
+#endif
 	}
 #endif
 #ifdef WITH_UN

--- src/proxymain.c	2026-07-04 18:51:28.000000000 +0800
+++ src/proxymain.c	2026-07-17 17:37:55.000000000 +0800
@@ -772,11 +772,13 @@
 			return -12;
 		    }
 #ifndef NOIPV6
+#ifdef IPV6_BOUND_IF
 	            if((*SAFAMILY(&srv.intsa) == AF_INET6 && srv.so._setsockopt(srv.so.state, sock, IPPROTO_IPV6, IPV6_BOUND_IF, &idx, sizeof(idx)))) {
 			dolog(&defparam, (unsigned char *)"failed to bind device");
 	        	return -12;
 	    	    }
 #endif
+#endif
 		}
 #endif
 	}