Chromecast Multicast Between SSID Subnet VLAN On Fortinet Fortigate

Enable Multicast Policy:
System -> Feature Visibility -> Additional Features > Multicast Policy -> On

Configure Multicast Policy:
Policy & Objects -> Multicast Policy

You'll need to create a policy going both ways between the desired networks and ensure that SNAT is enabled as well.

You may also need to disable multicast ttl changes via the CLI:

config system settings
set multicast-ttl-notchange enable
end

FortiWifi, 60D, FortiOS 6

Protect Against SYN Flood DDOS/DOS Denial Of Service Attacks

There are a few baseline variables you can set in the Linux kernel to help protect your server against SYN Floods.

echo 1 > /proc/sys/net/ipv4/tcp_syncookies
echo 2048 > /proc/sys/net/ipv4/tcp_max_syn_backlog
echo 3 > /proc/sys/net/ipv4/tcp_synack_retries

To make these persist across reboots, enter the following into /etc/sysctl.conf

net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_syn_backlog = 2048
net.ipv4.tcp_synack_retries = 3

It is also recommended you install CSF firewall to help your servers' security. CSF also includes SYN Flood mitigation at the firewall iptables/firewall level.

Enable Windows RDP Through Windows Firewall From Command Line

netsh firewall set portopening TCP 3389 microsoft-rdp

Disable cPanel cPHulk From The Command Line Console SSH

To Disable:

/usr/local/cpanel/bin/cphulk_pam_ctl --disable

--OR--

/usr/local/cpanel/etc/init/stopcphulkd stop

To Enable:

/usr/local/cpanel/bin/cphulk_pam_ctl --enable

Determine Version Of CSF From Command Line

csf -v

This will give you ALL the information, but if you want just the numeric version:

csf -v | cut -d ' ' -f 2

Block Outbound Port 25 SMTP For Untrusted Users With IPtables

This will only allow port 25 access to users: mail, mailman and root

iptables -A OUTPUT -d 127.0.0.1 -p tcp -m tcp --dport 25 -j ACCEPT
iptables -A OUTPUT -p tcp -m tcp --dport 25 -m owner --gid-owner mail -j ACCEPT
iptables -A OUTPUT -p tcp -m tcp --dport 25 -m owner --gid-owner mailman -j ACCEPT
iptables -A OUTPUT -p tcp -m tcp --dport 25 -m owner --uid-owner root -j ACCEPT
iptables -A OUTPUT -p tcp -m tcp --dport 25 -j REJECT --reject-with icmp-port-unreachable

Enable ICMP/Ping Through Windows Firewall Using The Command Line

netsh firewall set icmpsetting 8 enable

Stop Windows Firewall From The Command Line

netsh firewall set opmode disable

Start Windows Firewall From The Command Line

netsh firewall set opmode enable

Block Port 25 On SolusVM/Xen With IPtables

SolusVM (at the time of this writing) has no internal method for firewalling customers containers. I find it often necessary to restrict ports on customers (normally port 25) and after trial and error came up with some rules for IPtables to facilitate this at the hardware node level. SolusVM uses the FORWARD chain inside of IPtables so all you need to do is:

iptables -I FORWARD 1 -d $ip -p tcp -m tcp --dport 25 -j DROP
iptables -I FORWARD 1 -s $ip -p tcp -m tcp --dport 25 -j DROP

...where $ip is the IP you are restricting port traffic on. The above rules prevent all IN/OUT port 25 traffic to a particular host.

Installing CSF Firewall On Linux

cd /usr/local/src
wget https://download.configserver.com/csf.tgz
tar xfz csf.tgz
cd csf
./install.sh