From 562a4c056ea208e85e6f0551a188d55cee8050d5 Mon Sep 17 00:00:00 2001
From: neilpang <github@byneil.com>
Date: Sun, 5 Feb 2017 23:06:06 +0800
Subject: [PATCH] add note info if netcat-openbsd is required.

---
 acme.sh | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/acme.sh b/acme.sh
index ec41b60f..b22b2e69 100755
--- a/acme.sh
+++ b/acme.sh
@@ -61,6 +61,8 @@ DEFAULT_LOG_LEVEL="$LOG_LEVEL_1"
 
 _DEBUG_WIKI="https://github.com/Neilpang/acme.sh/wiki/How-to-debug-acme.sh"
 
+_PREPARE_LINK="https://github.com/Neilpang/acme.sh/wiki/Install-preparations"
+
 __INTERACTIVE=""
 if [ -t 1 ]; then
   __INTERACTIVE="1"
@@ -1684,6 +1686,14 @@ _startserver() {
     _NC="$_NC -6"
   fi
 
+  if [ "$Le_Listen_V4$Le_Listen_V6$ncaddr" ]; then
+    if ! _contains "$nchelp" "OpenBSD"; then
+      _err "The nc doesn't support '-4', '-6' or local-address, please install 'netcat-openbsd' and try again."
+      _err "See $(__green $_PREPARE_LINK)"
+      return 1
+    fi
+  fi
+
   if echo "$nchelp" | grep "\-q[ ,]" >/dev/null; then
     _NC="$_NC -q 1 -l $ncaddr"
   else