Gui
Select File / Open Network Stream. To receive an UDP/RTP unicast stream sent to your system, you should select the Force IPv6 option (and possibly adjust the destination UDP port). To receive an UDP multicast stream, select the UDP/RTP Multicast option, and specify the multicast address to subscribe to inside square brackets.
Commandline
vlc -vvv --ipv6 rtp://@[ff08::1]:5004
or sometimes in linux/unix
vlc -vvv -rtp:@//\[ff08::1\]:5004
Where you can change the RTP to UDP if you are streaming over UDP.