@lflorack 

Ditto for me...  Started May 27th and still happening.

Same thing happening here. Started April 29, but only four times from then until May 27. On May 27, I started getting them about once every half hour. I'll follow this thread. Hopefully, someone finds the cause and resolution. 

  @Wild-Wanderer I went back through my logs and found that my TCP no-Flag attacks started with multiple events daily on 27 May too. As an aside, I installed TL-R605 firmware v1.3.0 Build 20230511 on 17 May.  So, in my case anyway, it doesn't seem to have a direct correlation with the increase in the TCP no-Flag attacks.  in fact, I installed a pre-release version (v1.3.0 Build 20230424) on 28 April too.

lflorack wrote

  I installed TL-R605 firmware v1.3.0 Build 20230511 on 17 May.  So, in my case anyway, it doesn't seem to have a direct correlation with the increase in the TCP no-Flag attacks. 

Agreed. I just installed v1.3.0 today (29 May). 

  @lflorack 

The router currently does not support finding the source IP

so there isn't much you can do with it. it just detects and block TCP no-flag attack if that connection fits the rules. 

i don't think you should worry about it. if that bothers you, you can edit your log system.

if you want to know what is no-flag attack or should I worry about it? you need some lessons on TCP handshake and understand how internet works.

no big deal as long as your internet is find and stable when these occur. 

if you encounter an unstable network, and these alerts pop up at the same time, you need to consider if your IP is exposed/leaked during day to day net surfing. someone's attacking you. to fix this, sometimes you need help from your isp instead of the router. router can block but it increases the burden and potentially causes performance issues.

Hello @lflorack,

Thank you so much for taking the time to post the issue on TP-Link community!

To better assist you, I've created a support ticket via your registered email address, and escalated it to our support engineer to look into the issue. The ticket ID is TKID230547909, please check your email box and ensure the support email is well received. Thanks!

Once the issue is addressed or resolved, welcome to update this topic thread with your solution to help others who may encounter the same issue as you did.

Many thanks for your great cooperation and patience!

  @Hank21 

The email with ticket# has been received from support and responded to.