Is this traffic safe to be allowed?

[Netizen]

I have installed a new firewall on the hardware proxmox node and I see outgoing UDP traffic to the following IP:

kernel: Firewall: *UDP_OUT Blocked* IN= OUT=eth0 SRC=x.x.x.x DST=239.192.16.156 LEN=147 TOS=0x00 PREC=0x00 TTL=1 ID=0 DF PROTO=UDP SPT=5404 DPT=5405 LEN=127 UID=0 GID=0
(x.x.x.x = Proxmox HW node main IP)

I understand that this traffic relates to multicast (if I am correct). Is this same to be allowed in the firewall, and what is the potential negative effect if I block it?

I currently do not have a cluster but I have another server with IP addreses (subnet) that float from one server to the other for failover purposes.
Any comments are welcome

Thank you

 

[Netizen]

Anyone?

 

[dietmar]

You need that for cluster communication (else cluster will not work).