DOC: simplify bind option "interface" explanation
The current documentation of the bind option "interface" can be misleading
(as seen on the ML recently).
This patch tries to address misunderstandings by :
- avoiding the words listen or bind in the behavior description, using
"restrict to interface" instead
- using a different sentence construction (partially stolen from
"man 7 socket": SO_BINDTODEVICE)
- "defragmentation": moving behavior related explanations to the beginning
and restrictions, use-cases and requirements to the end.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 30647a9..5f7a65b 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -7126,14 +7126,13 @@
option can only be used when defining only a single socket.
interface <interface>
- Sets the name of the network interface to listen. This is currently only
- supported on Linux. The interface must be a primary system interface, not an
- aliased interface. When specified, all addresses on the same line will only
- be accepted if the incoming packets physically come through the designated
- interface. It is also possible to bind multiple frontends to the same address
- if they are bound to different interfaces. Note that binding to a network
- interface requires root privileges. This parameter is only compatible with
- TCPv4/TCPv6 sockets.
+ Restricts the socket to a specific interface. When specified, only packets
+ received from that particular interface are processed by the socket. This is
+ currently only supported on Linux. The interface must be a primary system
+ interface, not an aliased interface. It is also possible to bind multiple
+ frontends to the same address if they are bound to different interfaces. Note
+ that binding to a network interface requires root privileges. This parameter
+ is only compatible with TCPv4/TCPv6 sockets.
level <level>
This setting is used with the stats sockets only to restrict the nature of