SYNOPSIS

mcfirst [ -46vr ] [ -I interface ] [ -c count ] [ -t time ] [ source ] group port

DESCRIPTION

mcfirst can be used to check whether one can receive multicast packets from a host. The host may send any type of multicast packets, any application, IPv4 or IPv6, ASM or SSM. mcfirst joins the specified (source) and group, and listens to the specified port. mcfirst will by default exit when the first packet is received, and print how long it waited.

OPTIONS

The options are as follows.

-4

Force IPv4

-6

Force IPv6

-v

Print version

-r

Print rate information only

-I interface

Interface to join on

-c count

Stop after receiving count packets. Default is 1 unless time limit is specified

-t time

Exit after time seconds. Default is to exit after the first packet. If both count and time are specified, mcfirst will exit as soon as one of them is satisfied.

HISTORY

mcfirst was developed by Stig Venaas during the early days of the m6bone, the IPv6 multicast backbone.