From bd6cff7f9ce4e03ee1d8d624c9e3f4c923467a73 Mon Sep 17 00:00:00 2001
From: Lorenz Kästle <12514511+RincewindsHat@users.noreply.github.com>
Date: Wed, 27 Aug 2025 19:54:09 +0200
Subject: check_snmp: use snmp v2c if community is given

---
 plugins/check_snmp.c | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'plugins/check_snmp.c')

diff --git a/plugins/check_snmp.c b/plugins/check_snmp.c
index 7851631c..35e1f339 100644
--- a/plugins/check_snmp.c
+++ b/plugins/check_snmp.c
@@ -516,6 +516,7 @@ static process_arguments_wrapper process_arguments(int argc, char **argv) {
 	char *port = NULL;
 	char *miblist = NULL;
 	char *connection_prefix = NULL;
+	bool snmp_version_set_explicitely = false;
 	// TODO error checking
 	while (true) {
 		int option_char = getopt_long(
@@ -567,6 +568,8 @@ static process_arguments_wrapper process_arguments(int argc, char **argv) {
 			} else {
 				die(STATE_UNKNOWN, "invalid SNMP version/protocol: %s", optarg);
 			}
+			snmp_version_set_explicitely = true;
+
 			break;
 		case 'N': /* SNMPv3 context name */
 			config.snmp_session.contextName = optarg;
@@ -858,6 +861,11 @@ static process_arguments_wrapper process_arguments(int argc, char **argv) {
 		setenv("MIBS", miblist, 1);
 	}
 
+	// Historical default is SNMP v2c
+	if (!snmp_version_set_explicitely && config.snmp_session.community != NULL) {
+		config.snmp_session.version = SNMP_VERSION_2c;
+	}
+
 	if ((config.snmp_session.version == SNMP_VERSION_1) ||
 		(config.snmp_session.version == SNMP_VERSION_2c)) {     /* snmpv1 or snmpv2c */
 																/*
-- 
cgit v1.2.3-74-g34f1