From 5702f0f0a50c5a136d233ee379d71aeba0893325 Mon Sep 17 00:00:00 2001
From: Yaroslav Tykhiy <ytykhiy@gmail.com>
Date: Thu, 7 Feb 2008 11:00:42 +0000
Subject: [PATCH] Add a note that ipfw states do not implicitly match ICMP
 error messages.

---
 sbin/ipfw/ipfw.8 | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sbin/ipfw/ipfw.8 b/sbin/ipfw/ipfw.8
index 2c175ed020bb..67ed26225d04 100644
--- a/sbin/ipfw/ipfw.8
+++ b/sbin/ipfw/ipfw.8
@@ -2711,3 +2711,9 @@ ipfw nat is not compatible with the tcp segmentation offloading
 (TSO). Thus, to reliably nat your network traffic, please disable TSO
 on your NICs using
 .Xr ifconfig 8 .
+.Pp
+ICMP error messages are not implicitly matched by dynamic rules
+for the respective conversations.
+To avoid failures of network error detection and path MTU discovery,
+ICMP error messages may need to be allowed explicitly through static
+rules.