abnormal udp traffic detected, source port is zero, DROP (port53)

ktv

HI,
I have a lot of alerts like this:

but I dont know how is it possible if I have got a rule to block DNS serwer port (UDP 53) on my firewall (DNS_UDP is  set to UDP53 port).
Any advice? 

PeterUK

So its blocked what are you trying to do? stop it logging the block?

ktv

yep,
I dont know why I'm alerted if my port is closed (and Log denied traffic is set to no)

PeterUK

Its logging due to it being set in security policy > ADP > profile tab 

Zyxel_Jeff

Hi @ktv

 

Those logs were generated by UDP abnormal traffic protection of ADP.

So, even you disable DNS UDP port 53 session on security policy, those similar log messages still can be seen.

If you don’t want to see them you may navigate Configuration > Security Policy > ADP and set "Traffic Anomaly", "Protocol Anomaly" Log to “no”.

Hope this can help you.