root@mail:~# cat /etc/hosts  
 127.0.0.1 localhost  
 192.168.0.25 mail.serverkaka.com mail  

 root@mail:~# cat /etc/hostname  
 mail  

 root@mail:~# hostname -f   
 mail.serverkaka.com  

 root@mail:~# hostname   
 mail  

 sudo vim zimbra.sh  

 #!/bin/bash -x  
   
 # Zimbra mail server installation in Ubuntu 14.04 and 16.04  
 # Author: Subhash (serverkaka.com)  
   
 # Check if running as root  
 if [ "$(id -u)" != "0" ]; then  
   echo "This script must be run as root" 1>&2  
   exit 1  
 fi  
   
 ## Preparing all the variables like IP, Hostname, etc, all of them from the server  
 RANDOMHAM=$(date +%s|sha256sum|base64|head -c 10)  
 RANDOMSPAM=$(date +%s|sha256sum|base64|head -c 10)  
 RANDOMVIRUS=$(date +%s|sha256sum|base64|head -c 10)  
 HOSTNAME=$(hostname -s)  
   
 ##Install a DNS Server  
 sudo apt-get update && sudo apt-get install -y bind9 bind9utils bind9-doc  
 echo "Installing Bind DNS Server"  
 sed "s/-u/-4 -u/g" /etc/default/bind9 > /etc/default/bind9.new  
 mv /etc/default/bind9.new /etc/default/bind9  
 rm /etc/bind/named.conf.options  
 cat <<EOF >>/etc/bind/named.conf.options  
 options {  
 directory "/var/cache/bind";  
 listen-on { $2; }; # ns1 private IP address - listen on private network only  
 allow-transfer { none; }; # disable zone transfers by default  
 forwarders {  
 8.8.8.8;  
 8.8.4.4;  
 };  
 auth-nxdomain no; # conform to RFC1035  
 #listen-on-v6 { any; };  
 };  
 EOF  
 cat <<EOF >>/etc/bind/named.conf.local  
 zone "$1" {  
     type master;  
     file "/etc/bind/db.$1";  
 };  
 EOF  
 touch /etc/bind/db.$1  
 cat <<EOF >/etc/bind/db.$1  
 \$TTL 604800  
 @   IN   SOA  ns1.$1. root.localhost. (  
                 2    ; Serial  
             604800    ; Refresh  
             86400    ; Retry  
             2419200    ; Expire  
             604800 )   ; Negative Cache TTL  
   ;  
   @   IN   NS   ns1.$1.  
   @   IN   A   $2  
   @   IN   MX   10   $HOSTNAME.$1.  
   $HOSTNAME   IN   A   $2  
   ns1   IN   A   $2  
   mail   IN   A   $2  
   pop3   IN   A   $2  
   imap   IN   A   $2  
   imap4   IN   A   $2  
   smtp   IN   A   $2  
 EOF  
 sudo service bind9 restart  
   
 ##Preparing the config files to inject  
 echo "Creating the Scripts files"  
 mkdir /tmp/zcs && cd /tmp/zcs  
 touch /tmp/zcs/installZimbraScript  
 cat <<EOF >/tmp/zcs/installZimbraScript  
 AVDOMAIN="$1"  
 AVUSER="admin@$1"  
 CREATEADMIN="admin@$1"  
 CREATEADMINPASS="$3"  
 CREATEDOMAIN="$1"  
 DOCREATEADMIN="yes"  
 DOCREATEDOMAIN="yes"  
 DOTRAINSA="yes"  
 EXPANDMENU="no"  
 HOSTNAME="$HOSTNAME.$1"  
 HTTPPORT="8080"  
 HTTPPROXY="TRUE"  
 HTTPPROXYPORT="80"  
 HTTPSPORT="8443"  
 HTTPSPROXYPORT="443"  
 IMAPPORT="7143"  
 IMAPPROXYPORT="143"  
 IMAPSSLPORT="7993"  
 IMAPSSLPROXYPORT="993"  
 INSTALL_WEBAPPS="service zimlet zimbra zimbraAdmin"  
 JAVAHOME="/opt/zimbra/common/lib/jvm/java"  
 LDAPAMAVISPASS="$3"  
 LDAPPOSTPASS="$3"  
 LDAPROOTPASS="$3"  
 LDAPADMINPASS="$3"  
 LDAPREPPASS="$3"  
 LDAPBESSEARCHSET="set"  
 LDAPDEFAULTSLOADED="1"  
 LDAPHOST="$HOSTNAME.$1"  
 LDAPPORT="389"  
 LDAPREPLICATIONTYPE="master"  
 LDAPSERVERID="2"  
 MAILBOXDMEMORY="512"  
 MAILPROXY="TRUE"  
 MODE="https"  
 MYSQLMEMORYPERCENT="30"  
 POPPORT="7110"  
 POPPROXYPORT="110"  
 POPSSLPORT="7995"  
 POPSSLPROXYPORT="995"  
 PROXYMODE="https"  
 REMOVE="no"  
 RUNARCHIVING="no"  
 RUNAV="yes"  
 RUNCBPOLICYD="no"  
 RUNDKIM="yes"  
 RUNSA="yes"  
 RUNVMHA="no"  
 SERVICEWEBAPP="yes"  
 SMTPDEST="admin@$1"  
 SMTPHOST="$HOSTNAME.$1"  
 SMTPNOTIFY="yes"  
 SMTPSOURCE="admin@$1"  
 SNMPNOTIFY="yes"  
 SNMPTRAPHOST="$HOSTNAME.$1"  
 SPELLURL="http://$HOSTNAME.$1:7780/aspell.php"  
 STARTSERVERS="yes"  
 SYSTEMMEMORY="3.8"  
 TRAINSAHAM="ham.$RANDOMHAM@$1"  
 TRAINSASPAM="spam.$RANDOMSPAM@$1"  
 UIWEBAPPS="yes"  
 UPGRADE="yes"  
 USEKBSHORTCUTS="TRUE"  
 USESPELL="yes"  
 VERSIONUPDATECHECKS="TRUE"  
 VIRUSQUARANTINE="virus-quarantine.$RANDOMVIRUS@$1"  
 ZIMBRA_REQ_SECURITY="yes"  
 ldap_bes_searcher_password="$3"  
 ldap_dit_base_dn_config="cn=zimbra"  
 ldap_nginx_password="$3"  
 ldap_url="ldap://$HOSTNAME.$1:389"  
 mailboxd_directory="/opt/zimbra/mailboxd"  
 mailboxd_keystore="/opt/zimbra/mailboxd/etc/keystore"  
 mailboxd_keystore_password="$3"  
 mailboxd_server="jetty"  
 mailboxd_truststore="/opt/zimbra/common/lib/jvm/java/jre/lib/security/cacerts"  
 mailboxd_truststore_password="changeit"  
 postfix_mail_owner="postfix"  
 postfix_setgid_group="postdrop"  
 ssl_default_digest="sha256"  
 zimbraDNSMasterIP=""  
 zimbraDNSTCPUpstream="no"  
 zimbraDNSUseTCP="yes"  
 zimbraDNSUseUDP="yes"  
 zimbraDefaultDomainName="$1"  
 zimbraFeatureBriefcasesEnabled="Enabled"  
 zimbraFeatureTasksEnabled="Enabled"  
 zimbraIPMode="ipv4"  
 zimbraMailProxy="FALSE"  
 zimbraMtaMyNetworks="127.0.0.0/8 $2/32 [::1]/128 [fe80::]/64"  
 zimbraPrefTimeZoneId="America/Los_Angeles"  
 zimbraReverseProxyLookupTarget="TRUE"  
 zimbraVersionCheckInterval="1d"  
 zimbraVersionCheckNotificationEmail="admin@$1"  
 zimbraVersionCheckNotificationEmailFrom="admin@$1"  
 zimbraVersionCheckSendNotifications="TRUE"  
 zimbraWebProxy="FALSE"  
 zimbra_ldap_userdn="uid=zimbra,cn=admins,cn=zimbra"  
 zimbra_require_interprocess_security="1"  
 zimbra_server_hostname="$HOSTNAME.$1"  
 INSTALL_PACKAGES="zimbra-core zimbra-ldap zimbra-logger zimbra-mta zimbra-snmp zimbra-store zimbra-apache zimbra-spell zimbra-memcached zimbra-proxy"  
 EOF  
   
 touch /tmp/zcs/installZimbra-keystrokes  
 cat <<EOF >/tmp/zcs/installZimbra-keystrokes  
 y  
 y  
 y  
 y  
 y  
 n  
 y  
 y  
 y  
 y  
 y  
 y  
 y  
 n  
 y  
 y  
 EOF  
   
 ## Install Zimbra Mail Server  
 if [[ `lsb_release -rs` == "16.04" ]]; then  
      echo "Downloading Zimbra Collaboration 8.8.10 for Ubuntu 16.04"  
      wget https://files.zimbra.com/downloads/8.8.10_GA/zcs-8.8.10_GA_3039.UBUNTU16_64.20180928094617.tgz  
      tar xzvf zcs-*  
      echo "Installing Zimbra Collaboration just the Software"  
      cd /tmp/zcs/zcs-* && ./install.sh -s < /tmp/zcs/installZimbra-keystrokes  
      echo "Installing Zimbra Collaboration injecting the configuration"  
      /opt/zimbra/libexec/zmsetup.pl -c /tmp/zcs/installZimbraScript  
 fi  
 if [[ `lsb_release -rs` == "14.04" ]]; then  
      echo "Downloading Zimbra Collaboration 8.8.10 for Ubuntu 16.04"  
      wget https://files.zimbra.com/downloads/8.8.10_GA/zcs-8.8.10_GA_3039.UBUNTU14_64.20180928094617.tgz  
      tar xzvf zcs-*  
      echo "Installing Zimbra Collaboration just the Software"  
      cd /tmp/zcs/zcs-* && ./install.sh -s < /tmp/zcs/installZimbra-keystrokes  
      echo "Installing Zimbra Collaboration injecting the configuration"  
      /opt/zimbra/libexec/zmsetup.pl -c /tmp/zcs/installZimbraScript  
 fi  
   
 ## Restart Zimbra  
 su - zimbra -c 'zmcontrol restart'  
   
 ## Add Crontab for server autostart at startup or reboot   
 cat <(crontab -l) <(echo "@reboot su - zimbra -c 'zmcontrol start'") | crontab -  
   
 echo "You can access now to your Zimbra Collaboration Server"  
 echo "Admin Console: https://"$2":7071"  
 echo "Web Client: https://"$2  

 sudo chmod +x zimbra.sh  

 sudo ./zimbra.sh serverkaka.com 192.168.0.25 Zimbra123  

Now sit back and Relax, it will take time up to 30 minutes, depending on your internet and machine speed.

After Successfully script executed below is Access Zimbra Admin Portal & Web Mail Client.

To access Zimbra Mail Web Client, type the following URL in the browser
https://mail.serverkaka.com/

To access the Zimbra Admin Portal, type below URL in Web Browser
https://mail.serverkaka.com:7071/

Below Ports should be open in firewall for Zimbra access from external:

HTTP	80
HTTPS	443
POP3	110
SMTP	25
SMTP	587
POP3S (Secure POP3)	995
IMAP	143
IMAPS (Secure IMAP)	993

For more script and installation note check this link: https://github.com/SubhashPatel/Install-Zimbra-mail-server-ubuntu

Also read: Configure Let's Encrypt SSL in Zimbra Mail Server