Thanks for your feedback.

I am very sorry for misunderstanding you that
our DOS protection function is preventing the local device in LAN to attack the device in internet.
when enable DOS protection function,and set the ICMP(UDP,TCP) FLOOD Packets Threshold,
if the packets sent from the LAN device exceed the threshold,the LAN device will be added into the block.
This is design idea of our DOS protection function,it is not a bug.

If you need this function,here is an advice that set the threshold for a higher value.
because our C7 is a NAT device,it is not necessary to enable DOS protection function for security.

Hope this may do something for help.
Looking forward to your reply.

But my LAN device (my computer) did not send an amount of packets that
exceeded the threshold, it's the other address in WAN who sent those
packets to my device.

Is there a way to access SSH on the router using original firmware? I would
like to change the way DoS protection works.

Thanks for your reply.
Based on three handshakes of TCP, when your WAN device access your LAN web server,your web server will reply packets according to the request.
Unfortunately our router does not support SSH telnet,and it is unable to change the way DoS protection works.
However,because our router is a NAT device,it is not necessary to enable DOS protection function for security.

feardc wrote

That's how all ended up for me, but I keep saying: What kind of DoS protection is one that blocks the hoster himself? Totally useless! :/

I know this is an old thread, but if you do still want this DoS enabled, setting ICMP, UDP, TCP-SYN FLOOD settings to "High" should take care of it.  I experienced this on my Android phone when all other devices were working fine because I started syncing my photos/videos with Google Photos.  It would connect and almost automatically popped my phone on the blocked list.  Setting it to "Medium" still had it listed, but switching it to high allowed it to successfully backup my photos/videos without further issues.