1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. SNBForums Code of Conduct

    SNBForums is a community for everyone, no matter what their level of experience.

    Please be tolerant and patient of others, especially newcomers. We are all here to share and learn!

    The rules are simple: Be patient, be nice, be helpful or be gone!

    Dismiss Notice
Dismiss Notice

Welcome To SNBForums

SNBForums is a community for anyone who wants to learn about or discuss the latest in wireless routers, network storage and the ins and outs of building and maintaining a small network.

If you'd like to post a question, simply register and have at it!

While you're at it, please check out SmallNetBuilder for product reviews and our famous Router Charts, Ranker and plenty more!

Possible SYN flooding on port 8200. Sending cookies.

Discussion in 'Asuswrt-Merlin' started by umrico, Feb 13, 2020 at 7:14 PM.

  1. umrico

    umrico New Around Here

    Joined:
    Oct 25, 2019
    Messages:
    3
    Good Day,

    I keep getting the following a couple times a minute and I can't figure out what it is for the life of me. How can I troubleshoot this? TIA for your help it is greatly appreciated!!!

    Feb 13 18:58:17 kernel: TCP: Possible SYN flooding on port 8200. Sending cookies.
    Feb 13 18:58:17 kernel: TCP: Possible SYN flooding on port 8200. Sending cookies.
    Feb 13 18:58:22 kernel: TCP: Possible SYN flooding on port 8200. Sending cookies.
    Feb 13 18:58:22 kernel: TCP: Possible SYN flooding on port 8200. Sending cookies.
    Feb 13 18:58:22 kernel: TCP: Possible SYN flooding on port 8200. Sending cookies.
    Feb 13 18:58:22 kernel: TCP: Possible SYN flooding on port 8200. Sending cookies.
    Feb 13 18:58:22 kernel: TCP: Possible SYN flooding on port 8200. Sending cookies.
    Feb 13 18:58:22 kernel: TCP: Possible SYN flooding on port 8200. Sending cookies.
     
  2. ColinTaylor

    ColinTaylor Part of the Furniture

    Joined:
    Mar 31, 2014
    Messages:
    10,573
    Location:
    UK
    Router model?
    Firmware version?

    Do you have the router's Media Server enabled? Have you disabled the router's firewall?
     
  3. umrico

    umrico New Around Here

    Joined:
    Oct 25, 2019
    Messages:
    3
    Rt-ac-68u

    FW 384.15. it's happened on at least the last 3 versions that I have noticed anyway.

    Upnp media server was turned on. I don't recall flipping that on. That may have instantly solved the problem.A that's the problem, why would that be?

    Firewall is on.

    Thanks again for you help! Googled this forever and tried running a wireshark but couldn't see the problem!
     
  4. ColinTaylor

    ColinTaylor Part of the Furniture

    Joined:
    Mar 31, 2014
    Messages:
    10,573
    Location:
    UK
    If the firewall in on then I can only assume that something on your LAN is spamming the media server. To discover what you'd have to run tcpdump on the router, or systematically turn each device on your LAN off until you find the culprit. I'd suspect devices like smart TV's or media servers (e.g. Roku, AppleTV, etc.).
     
  5. umrico

    umrico New Around Here

    Joined:
    Oct 25, 2019
    Messages:
    3
    Thank you so much for your help i appreciate!