Provided by: freebsd-manpages_11.1-3_all 
NAME
mld — Multicast Listener Discovery Protocol
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <netinet6/mld6.h>
int
socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
DESCRIPTION
MLD is a control plane protocol used by IPv6 hosts and routers to propagate multicast group membership
information. Normally this protocol is not used directly, except by the kernel itself, in response to
multicast membership requests by user applications. Multicast routing protocol daemons may open a raw
socket to directly interact with mld and receive membership reports.
As of FreeBSD 8.0, MLD version 2 is implemented. This adds support for Source-Specific Multicast (SSM),
whereby applications may communicate to upstream multicast routers that they are only interested in
receiving multicast streams from particular sources. The retransmission of state-change reports adds some
robustness to the protocol.
SYSCTL VARIABLES
net.inet6.mld.ifinfo
This opaque read-only variable exposes the per-link MLDv2 status to ifmcstat(8).
net.inet6.mld.gsrdelay
This variable specifies the time threshold, in seconds, for processing Group-and-Source Specific
Queries (GSR). As GSR query processing requires maintaining state on the host, it may cause memory
to be allocated, and is therefore a potential attack point for Denial-of-Service (DoS). If more
than one GSR query is received within this threshold, it will be dropped, to mitigate the potential
for DoS.
net.inet6.mld.v1enable
If this variable is non-zero, then MLDv1 membership queries (and host reports) will be processed by
this host, and backwards compatibility will be enabled until the v1 'Older Version Querier Present'
timer expires. This sysctl is normally enabled by default.
SEE ALSO
netstat(1), sourcefilter(3), icmp6(4), inet(4), multicast(4), ifmcstat(8)
HISTORY
The mld manual page appeared in FreeBSD 8.0.