Looking for a tool that can determine TCP settings of a server.

I was just evaluating whether to enable SACK and thought I might like to check what others are doing, but couldn't figure out a way.

  • Too generic. You can do that with netstat if you want Dec 15, 2021 at 9:02
  • @FrancescoMantovani If that works, great. How do I use netstat to determine if, say, the stackexchange.com server can use SACK?
    – Paul
    Dec 15, 2021 at 12:55

1 Answer 1


I see, you are looking for the SACK Panic vulnerability.

In this case you can use:

  • Wireshark: through this guide
  • tcpdump: through this command tcpdump -i eth0 -n 'ip[8]<65 and tcp[13]&0x2f=2' | grep 'sackOK'

Next time for security questions post on https://security.stackexchange.com/

  • Thank you. I hadn't got that far as I was just initially curious to see what others are doing.
    – Paul
    Dec 15, 2021 at 23:27

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.