will configure a linux machine to route multicast trafic and start a dhcp server

route_dhcp_multicast.sh

#!/bin/bash
#stop on error
set -e
LOCAL_IF="enp2s0"
UPSTREAM_IF="enp2s0"
ifconfig ${LOCAL_IF} 192.168.2.1 netmask 255.255.255.0 broadcast 192.168.2.255

# Disabled by default!
echo "1" > /proc/sys/net/ipv4/ip_forward

# Load various modules. Usually they are already loaded 
# (especially for newer kernels), in that case 
# the following commands are not needed.

# Load iptables module:
modprobe ip_tables

# activate connection tracking
# (connection's status are taken into account)
modprobe ip_conntrack

# Special features for IRC:
modprobe ip_conntrack_irc

#Special features for FTP:
modprobe ip_conntrack_ftp

iptables -t nat -A POSTROUTING -o ${UPSTREAM_IF} -j MASQUERADE

echo 40 > /proc/sys/net/ipv4/igmp_max_msf
echo "2" > /proc/sys/net/ipv4/conf/${LOCAL_IF}/force_igmp_version
#forward all multicast traffic
ip route add 224.0.0.0/4 dev ${LOCAL_IF}

#setup dhcp server
cat <<EOF
option domain-name-servers 192.168.1.1;
option subnet-mask 255.255.255.0;
option routers 192.168.2.1;

subnet 192.168.2.0 netmask 255.255.255.0 {
  range 192.168.2.150 192.168.2.250;
}
EOF > /tmp/dhcpd_tmp.conf
#start dhcp server
/usr/bin/dhcpd -4 -q -cf /tmp/dhcpd_tmp.conf -pf /run/dhcpd4.pid ${LOCAL_IF}