TCP/IP hardening, take two

1999-07-27 Thread Dag-Erling Smorgrav
I cleaned up the previously posted patches, tested them a little more, and added a sysctl knob for logging SYN+FIN packets (before optionally dropping them). A FreeBSD 4.0-CURRENT machine with these patches and no firewall looks like this to nmap (with tcp.drop_synfin and tcp.restrict_rst enabled)

TCP/IP hardening, take two

1999-07-27 Thread Dag-Erling Smorgrav
I cleaned up the previously posted patches, tested them a little more, and added a sysctl knob for logging SYN+FIN packets (before optionally dropping them). A FreeBSD 4.0-CURRENT machine with these patches and no firewall looks like this to nmap (with tcp.drop_synfin and tcp.restrict_rst enabled

TCP/IP hardening

1999-07-26 Thread Dag-Erling Smorgrav
Attached are patches which implement four new sysctl variables: * net.inet.icmp.dropredirect: if set to 1, ignore ICMP REDIRECT packets. * net.inet.icmp.logredirect: if set to 1, log all ICMP REDIRECT packets (before optionally dropping them). * net.inet.tcp.restrict_rst: if set to 1, d

TCP/IP hardening

1999-07-26 Thread Dag-Erling Smorgrav
Attached are patches which implement four new sysctl variables: * net.inet.icmp.dropredirect: if set to 1, ignore ICMP REDIRECT packets. * net.inet.icmp.logredirect: if set to 1, log all ICMP REDIRECT packets (before optionally dropping them). * net.inet.tcp.restrict_rst: if set to 1,