fields of expertise: c/c++, java, bash shell scripting, client/server programming, threads programming, embarcadero rad studio, asterisk/elastix/freepbx, linux sysadmin, email/spf/dkim/dmarc, Postfix/Sendmail/Exim/Zimbra, dns, whm/cpanel, webmin/virtualmin/cloudmin, xenserver/vmware, aws/ec2, firewalls, vpn/openvpn/ipsec, mikrotik, iscsi, nexentastor, freenas and many more.