UDP is a connectionless communication protocol used in applications like gaming, playing videos, and DNS lookups. Most of its usage is in time-sensitive applications.
Despite it’s faster communication, it is prone to security vulnerabilities and attacks such as DDoS attacks and IP spoofing.
Why block UDP traffic? UDP does not provide for congestion control. It continues to transmit traffic at the desired rate and does nothing to avoid congestion, which can lead to network collapse.
To block all UDP traffic in your Mikrotik router
/ip firewall filter add action=drop protocol=udp chain=forwardTo block all UDP traffic except port 53(used for DNS)
/ip firewall filter add action=drop protocol=udp port=!53 chain=forwardBlocking UDP traffic using winbox
Login to winbox
go to IP->Firewall
add a new filter rule
select Chain: forward, Protocol: udp
go to action, set action: drop. Click apply.
You just blocked UDP traffic in your mikrotik router.