@mauve also, just played around with #socat and #reuseaddr and #reuseport a bit. For #UDP #unicast, this did not help, only one socat client receives the packet on Linux. However with #IPv6 #multicast on Linux this seems to work fine, receiving with multiple clients listening on the same UDP port on the same host when using SO_REUSEADDR/SO_REUSEPORT?