diff --git a/src/core/symbol.c b/src/core/symbol.c
index 32af085..2a404b9 100644
--- a/src/core/symbol.c
+++ b/src/core/symbol.c
@@ -114,6 +114,7 @@
     NN_SYM(NN_PROTOCOL, SOCKET_OPTION, INT, NONE),
     NN_SYM(NN_IPV4ONLY, SOCKET_OPTION, INT, BOOLEAN),
     NN_SYM(NN_SOCKET_NAME, SOCKET_OPTION, STR, NONE),
+    NN_SYM(NN_MAXTTL, SOCKET_OPTION, INT, NONE),
 
     NN_SYM(NN_SUB_SUBSCRIBE, TRANSPORT_OPTION, STR, NONE),
     NN_SYM(NN_SUB_UNSUBSCRIBE, TRANSPORT_OPTION, STR, NONE),