INADDR_ANY has nothing to do with the IP_MULTICAST_ALL option. It does not matter if the interface is bound to all interfaces or a particular interface for the functionality of IP_MULTICAST_ALL. Multicast datagrams are addressed to a multicast IP address and will enter the network stack via a particular interface. The application can choose from which interface it will receive multicast data by binding the socket to an IP address. It can then use the IP_MULTICAST_ALL option to restrict the multicast groups that the IP stack will deliver via the socket. Signed-off-by: Christoph Lameter <cl@xxxxxxxxx> Index: manpages-5.10/man7/ip.7 =================================================================== --- manpages-5.10.orig/man7/ip.7 +++ manpages-5.10/man7/ip.7 @@ -571,10 +571,7 @@ that wish to deliberately send probe pac the observed Path MTU. .TP .BR IP_MULTICAST_ALL " (since Linux 2.6.31)" -This option can be used to modify the delivery policy of multicast messages -to sockets bound to the wildcard -.B INADDR_ANY -address. +This option can be used to modify the delivery policy of multicast messages. The argument is a boolean integer (defaults to 1). If set to 1, the socket will receive messages from all the groups that have been joined
