diff -urNp a/snmplib/snmp_api.c b/snmplib/snmp_api.c
--- a/snmplib/snmp_api.c	2020-11-26 11:05:51.084788775 +0100
+++ b/snmplib/snmp_api.c	2020-11-26 11:08:27.850751397 +0100
@@ -235,7 +235,7 @@ static const char *api_errors[-SNMPERR_M
     "No error",                 /* SNMPERR_SUCCESS */
     "Generic error",            /* SNMPERR_GENERR */
     "Invalid local port",       /* SNMPERR_BAD_LOCPORT */
-    "Unknown host",             /* SNMPERR_BAD_ADDRESS */
+    "Invalid address",          /* SNMPERR_BAD_ADDRESS */
     "Unknown session",          /* SNMPERR_BAD_SESSION */
     "Too long",                 /* SNMPERR_TOO_LONG */
     "No socket",                /* SNMPERR_NO_SOCKET */
@@ -1662,7 +1662,9 @@ _sess_open(netsnmp_session * in_session)
         DEBUGMSGTL(("_sess_open", "couldn't interpret peername\n"));
         in_session->s_snmp_errno = SNMPERR_BAD_ADDRESS;
         in_session->s_errno = errno;
-        snmp_set_detail(in_session->peername);
+        if (!netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID,
+                                    NETSNMP_DS_LIB_CLIENT_ADDR))
+            snmp_set_detail(in_session->peername);
         return NULL;
     }