4 ms·

Can someone explain what this line in the feature section mean? Telnet brute-force IP banning by sending UDP packets to a firewall host

• pyritschard 4y ago
  It refers to a technique also known as "port knocking" which consists of leaving a port closed by default and opening it upon receiving a message by another channel (in this case, a UDP packet). It was mostly in use when TLS hadn't made it's way into most common protocols
  • justusthane 4y ago
    No, that’s not what this is referring to, since that doesn’t involve blocking IPs. This page[1] provides some detail: > A recent change goes a step further and sends a UDP packet to my OpenBSD firewall containing the IP to be banned, and a small Ruby server running there adds the IP to a pf table, immediately blocking all further IP access from the bot. [1]: https://jcs.org/2022/07/15/kludge https://jcs.org/2022/07/15/kludge
    • hexmiles 4y ago
      Thank you,