Add LocalDiscovery option which tries to detect peers on the local network.

[tinc] / doc / tinc.conf.5.in

diff --git a/doc/tinc.conf.5.in b/doc/tinc.conf.5.in
index 6853bae..a6ae4f5 100644 (file)
--- a/doc/tinc.conf.5.in
+++ b/doc/tinc.conf.5.in
@@ -150,6 +150,9 @@ It is possible to bind only to a single interface with this variable.
 .Pp
 This option may not work on all platforms.
 
+.It Va Broadcast Li = yes | no Po yes Pc Bq experimental
+When disabled, tinc will drop all broadcast and multicast packets, in both router and switch mode.
+
 .It Va ConnectTo Li = Ar name
 Specifies which other tinc daemon to connect to on startup.
 Multiple
@@ -168,6 +171,14 @@ If you don't specify a host with
 won't try to connect to other daemons at all,
 and will instead just listen for incoming connections.
 
+.It Va DecrementTTL Li = yes | no Po yes Pc
+When enabled,
+.Nm tinc
+will decrement the Time To Live field in IPv4 packets, or the Hop Limit field in IPv6 packets,
+before forwarding a received packet to the virtual network device or to another node,
+and will drop packets that have a TTL value of zero,
+in which case it will send an ICMP Time Exceeded packet back.
+
 .It Va Device Li = Ar device Po Pa /dev/tap0 , Pa /dev/net/tun No or other depending on platform Pc
 The virtual network device to use.
 .Nm tinc
@@ -222,23 +233,23 @@ it can be used to change the way packets are interpreted:
 
 .Bl -tag -width indent
 
-.It tun Pq BSD only
+.It tun Pq BSD and Linux
 Set type to tun.
 Depending on the platform, this can either be with or without an address family header (see below).
 
-.It tunnohead Pq BSD only
+.It tunnohead Pq BSD
 Set type to tun without an address family header.
 Tinc will expect packets read from the virtual network device to start with an IP header.
 On some platforms IPv6 packets cannot be read from or written to the device in this mode.
 
-.It tunifhead Pq BSD only
+.It tunifhead Pq BSD
 Set type to tun with an address family header.
 Tinc will expect packets read from the virtual network device
 to start with a four byte header containing the address family,
 followed by an IP header.
 This mode should support both IPv4 and IPv6 packets.
 
-.It tap Pq BSD only
+.It tap Pq BSD and Linux
 Set type to tap.
 Tinc will expect packets read from the virtual network device
 to start with an Ethernet header.
@@ -309,6 +320,18 @@ This option controls the period the encryption keys used to encrypt the data are
 It is common practice to change keys at regular intervals to make it even harder for crackers,
 even though it is thought to be nearly impossible to crack a single key.
 
+.It Va LocalDiscovery Li = yes | no Po no Pc Bq experimental
+When enabled,
+.Nm tinc
+will try to detect peers that are on the same local network.
+This will allow direct communication using LAN addresses, even if both peers are behind a NAT
+and they only ConnectTo a third node outside the NAT,
+which normally would prevent the peers from learning each other's LAN address.
+
+.Pp
+Currently, local discovery is implemented by sending broadcast packets to the LAN during path MTU discovery.
+This feature may not work in all possible situations.
+
 .It Va MACExpire Li = Ar seconds Pq 600
 This option controls the amount of time MAC addresses are kept before they are removed.
 This only has effect when