fix #2482 snmp response: Too long
diff --git a/snmplib/snmp_api.c b/snmplib/snmp_api.c
index ee32eba..45267fd 100644
--- a/snmplib/snmp_api.c
+++ b/snmplib/snmp_api.c
@@ -4871,7 +4871,7 @@
      * specified in the received PDU.  
      */
 
-    if (session->sndMsgMaxSize != 0 && length > session->sndMsgMaxSize) {
+    if (pdu->version == SNMP_VERSION_3 && session->sndMsgMaxSize != 0 && length > session->sndMsgMaxSize) {
         DEBUGMSGTL(("sess_async_send",
                     "length of packet (%lu) exceeds session maximum (%lu)\n",
                     length, session->sndMsgMaxSize));