diff --git a/debian/patches/18_check_snmp_int_fix_perf_out b/debian/patches/18_check_snmp_int_fix_perf_out
new file mode 100644
index 0000000..59bc9c7
--- /dev/null
+++ b/debian/patches/18_check_snmp_int_fix_perf_out
@@ -0,0 +1,43 @@
+From effd196f76c4f4e9505b0955b020f8f65f1700a2 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Pawe=C5=82=20Szafer?= <pszafer@gmail.com>
+Date: Mon, 16 Mar 2020 18:41:49 +0100
+Subject: [PATCH] fix perf_out not defined error
+
+---
+ plugins/check_snmp_int.pl | 9 +++++----
+ 1 file changed, 5 insertions(+), 4 deletions(-)
+
+diff --git a/plugins/check_snmp_int.pl b/plugins/check_snmp_int.pl
+index 6e42163..1f0cdc2 100755
+--- a/plugins/check_snmp_int.pl
++++ b/plugins/check_snmp_int.pl
+@@ -993,24 +993,25 @@ sub check_options {
+ 
+ # Check if all interface are OK
+ if ($num_ok == $num_int) {
++    my $is_perf_defined = defined($perf_out) && defined($o_perf);
+     if ($final_status == 0) {
+         print $print_out, ":", $num_ok, " UP: OK";
+-        if (defined($o_perf)) { print " | ", $perf_out; }
++        if ($is_perf_defined) { print " | ", $perf_out; }
+         print "\n";
+         exit $ERRORS{"OK"};
+     } elsif ($final_status == 1) {
+         print $print_out, ":(", $num_ok, " UP): WARNING";
+-        if (defined($o_perf)) { print " | ", $perf_out; }
++        if ($is_perf_defined) { print " | ", $perf_out; }
+         print "\n";
+         exit $ERRORS{"WARNING"};
+     } elsif ($final_status == 2) {
+         print $print_out, ":(", $num_ok, " UP): CRITICAL";
+-        if (defined($o_perf)) { print " | ", $perf_out; }
++        if ($is_perf_defined) { print " | ", $perf_out; }
+         print "\n";
+         exit $ERRORS{"CRITICAL"};
+     } else {
+         print $print_out, ":(", $num_ok, " UP): UNKNOWN";
+-        if (defined($perf_out)) { print " | ", $perf_out; }
++        if ($is_perf_defined) { print " | ", $perf_out; }
+         print "\n";
+         exit $ERRORS{"UNKNOWN"};
+     }
diff --git a/debian/patches/series b/debian/patches/series
index 421df72..82505fe 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -6,5 +6,6 @@
 15_check_snmp_int_spaces
 16_check_snmp_win_max_message_size
 17_check_snmp_storage_okifempty
+18_check_snmp_int_fix_perf_out
 50_disable_epn
 51_fix_privacy_doc