Disabilitare pings e icmp

[serverplan]

Accedere tramite ssh sul server e editare il seguente file

nano /etc/sysctl.conf

aggiungere alla fine del file il seguente testo

# disable packet forwarding
net.ipv4.ip_forward = 0
# enable source route verification
net.ipv4.conf.all.rp_filter = 1
# ignore broadcast pings
net.ipv4.icmp_echo_ignore_broadcasts = 1
# enable syn cookies
net.ipv4.tcp_syncookies = 1
# size of syn backlog
net.ipv4.tcp_max_syn_backlog = 512
# disable automatic defragmentation 
# set max files
fs.file-max = 32768
# Enable IP spoofing protection, turn on Source Address Verification
net.ipv4.conf.all.rp_filter = 1
# Enable TCP SYN Cookie Protection
net.ipv4.tcp_syncookies = 1
# Enable ignoring ping request
net.ipv4.icmp_echo_ignore_all = 1

editare il file /etc/rc.local

nano /etc/rc.local

e aggiungere alla fine del file

for f in /proc/sys/net/ipv4/conf/*/rp_filter; do
echo 1 >
done
echo 1 > /proc/sys/net/ipv4/tcp_syncookies
for f in /proc/sys/net/ipv4/conf/*/accept_source_route; do
echo 0 >
done
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all

editiamo il file

nano /etc/host.conf

e aggiungiamo

# Lookup names via DNS first then fall back to /etc/hosts.
order bind,hosts
# We have machines with multiple IP addresses.
multi on
# Check for IP address spoofing.
nospoof on

riavviamo la macchina con

reboot