Find source and destination of TCP and UDP DOS floods

I enabled DOS Protection and since then every minute sophos is droping some TCP traffic and sometimes UDP, I'm sure Im not getting attacked and just need to add a DOS bypass rule. My question is where in Sophos XG v18 can in find the Source and destination details of traffic that has been dropped because of the DOS protection. FYI, I've never used a firewall before and my first one is this so sorry it its a basic question. I can see logs and current activity and sure there must be some way to filter it to find this but not sure how. 

  • Hi  

    from Intrusion Prevention >> DoS Attacks

    DoS attack status allows you to see if traffic limits have been applied and the amount of data dropped after the limit has been exceeded. The firewall applies the traffic limits specified in DoS settings and logs the corresponding events. Data is available for the source and destination in real-time.

    • To view the attack details, click an attack type.
    • When you click on attack type, it will pop up a window and will provide flooder IP if the system detects it.

    For Configuration and in-depth details, I would recommend you to check the article -

  • In reply to Keyur:

    Hi Keyur,

    Thanks for the quick reply, that will definitely help with UDP.

    For TCP Flood i noticed that in your picture and also on my firewall that the hyperlink to view the details is not available. Is there anything for the TCP Flood side?

  • In reply to Michael007:


    SYN/TCP Flood: A SYN flood is when a host sends a flood of TCP/SYN packets, often with a forged sender address. Every packet is handled like a connection request; this causes the server to spawn a half-open connection because it sends back a TCP/SYN-ACK packet (Acknowledge) and waits for a packet in response from the sender address (the response to the ACK Packet). However, as the sender's address is forged, the response never comes. These half-open connections occupy the number of available connections the server is able to make and keep it from responding to legitimate requests until after the attack ends.

    If any IP detects under flooding will be visible under SYN flood as TCP and SYN are part of the same mechanism, moreover, we do not recommend to apply TCP flood until it specifically required and directed by the support, I will try to collect further info on TCP flood tab and share with you if there is a different behavior.

  • In reply to Keyur:

    Thanks Keyur, will disable the TCP flood for now and monitor the UDP with the method you mention, appreciate your help

  • In reply to Michael007:


    Please reach out to us if you need further assistance. We will glad to assist you further.