Disabling TCP Timestamp response on FreeBSD
Taken from Rapid7 Vulnerabilities page:
Description
The remote host responded with a TCP timestamp. The TCP timestamp response can be used to approximate the remote host's uptime, potentially aiding in further attacks. Additionally, some operating systems can be fingerprinted based on the behavior of their TCP timestamps.
Solution
Disable TCP timestamp responses on FreeBSD
Set the value of net.inet.tcp.rfc1323 to 0 by running the following command:
sysctl -w net.inet.tcp.rfc1323=0
Additionally, put the following value in the default sysctl configuration file, generally sysctl.conf:
net.inet.tcp.rfc1323=0
