proper way to configure /etc/hosts

ISPCONFIG3 on Debian 8.8 single server
Everything works but I am having issues with setting up DNS Records and was not sure how to configure /etc/hosts and was not sure how to properly configure webserver, name server(s) and email server.

/etc/hosts
127.0.0.1 localhost.localdomain localhost
xxx.xxx.xxx.170 server1.mydomain.com server1

# The following lines are desirable for IPv6 capable hosts
::1 localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
-------------------------
/etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static

address xxx.xxx.xxx.170
netmask 255.255.255.248
network xxx.xxx.xxx.168
broadcast xxx.xxx.xxx.175
gateway xxx.xxx.xxx.169

# The secondary network interface
auto eth0:0
iface eth0:0 inet static

address xxx.xxx.xxx.171
netmask 255.255.255.248
network xxx.xxx.xxx.168
broadcast xxx.xxx.xxx.175
gateway xxx.xxx.xxx.169

# The third network interface
auto eth0:1
iface eth0:1 inet static

address xxx.xxx.xxx.172
netmask 255.255.255.248
network xxx.xxx.xxx.168
broadcast xxx.xxx.xxx.175
gateway xxx.xxx.xxx.169

# The fourth network interface
auto eth0:2
iface eth0:2 inet static

address xxx.xxx.xxx.173
netmask 255.255.255.248
network xxx.xxx.xxx.168
broadcast xxx.xxx.xxx.175
gateway xxx.xxx.xxx.169

# The Fith network interface
auto eth0:3
iface eth0:3 inet static

address xxx.xxx.xxx.174
netmask 255.255.255.248
network xxx.xxx.xxx.168
broadcast xxx.xxx.xxx.175
gateway xxx.xxx.xxx.169
-------------

 

Thanks Till