From 6aad01abbd61e523414051ad9d13317784d989a5 Mon Sep 17 00:00:00 2001
From: Georg Lauterbach <44545919+aendeavor@users.noreply.github.com>
Date: Sun, 27 Sep 2020 22:14:27 +0200
Subject: [PATCH] added warning message for PERMIT_DOCKER=network when using
 IPv6 (#1405)

---
 docs/content/config/troubleshooting/faq.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/docs/content/config/troubleshooting/faq.md b/docs/content/config/troubleshooting/faq.md
index 002f8164..99595209 100644
--- a/docs/content/config/troubleshooting/faq.md
+++ b/docs/content/config/troubleshooting/faq.md
@@ -270,6 +270,8 @@ Please note that clamav can consume a lot of memory, as it reads the entire sign
 
 Yes, by Adding the Environment Variable `PERMIT_DOCKER: network`.
 
+**WARNING**: Adding the docker network's gateway to the list of trusted hosts, e.g. using the `network` or `connected-networks` option, can create an [**open relay**](https://en.wikipedia.org/wiki/Open_mail_relay), [for instance](https://github.com/tomav/docker-mailserver/issues/1405#issuecomment-590106498) if IPv6 is enabled on the host machine but not in Docker. ([#1405](https://github.com/tomav/docker-mailserver/issues/1405))
+
 ### How can I authenticate users with SMTP_ONLY?
 
 See https://github.com/tomav/docker-mailserver/issues/1247 for an example.