DOC: Clarify IPv4 address / mask notation rules
Adds some examples regarding shorthand IPv4 address notation which might
be confused with RFC 4632 CIDR notation, leading to different than
expected results.
(cherry picked from commit eba5634f2c6d0eced75aacd28a5ae5e5d0613911)
(cherry picked from commit ed241d181d096fe1e1c709cc9addb5d981527ee0)
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 6c7c33c..38c7555 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -9850,6 +9850,21 @@
does not depend on any random DNS match at the moment the configuration is
parsed.
+The dotted IPv4 address notation is supported in both regular as well as the
+abbreviated form with all-0-octets omitted:
+
+ +------------------+------------------+------------------+
+ | Example 1 | Example 2 | Example 3 |
+ +------------------+------------------+------------------+
+ | 192.168.0.1 | 10.0.0.12 | 127.0.0.1 |
+ | 192.168.1 | 10.12 | 127.1 |
+ | 192.168.0.1/22 | 10.0.0.12/8 | 127.0.0.1/8 |
+ | 192.168.1/22 | 10.12/8 | 127.1/8 |
+ +------------------+------------------+------------------+
+
+Notice that this is different from RFC 4632 CIDR address notation in which
+192.168.42/24 would be equivalent to 192.168.42.0/24.
+
IPv6 may be entered in their usual form, with or without a netmask appended.
Only bit counts are accepted for IPv6 netmasks. In order to avoid any risk of
trouble with randomly resolved IP addresses, host names are never allowed in