- Design and maintenance of network systems physical and logical, ( Wired and Wireless radius and LDAP, VLANs, OSPF, BGP routing)- Design, build, and maintain complex IT networks ( Cisco, Tp-Link, Unify )- Build and maintain firewalls ( Iptables, Mikrotik, Wachguard, PfSense)- Build and maintain Linux servers (Database, DNS, Web, LAMP, LEMP, Ftp etc)- Implement network and server monitoring systems (Icinga/Nagios, Cacti, Munin, Zabbix, LibreNms )- Debugging of network problems (TCP/IP, PPOE, etc)- Write a unique customer management system (Perl, Bash, Html, Php)- Linux (Debian,Ubuntu,Centos,SLES + OES) install and maintenance- Windows 2003/2008/2012/2016/2019 install and maintenance (Remote desktop, Active Directory and connected services)- Build and maintain VPN networks (OpenVPN, Ipsec, Storngswan, Wireguard )- Build and maintain file and print servers (SLES OES + iPrint, Windows,Linux CUPS)- Build and maintain complete email and workgroup solutions (SLES,OES, Groupwise, Postfix, Spamassassin, Amavis, Clamav, Proxmox Mail Gateway )- ERP system maintenance, writing database queries, data examination, and findsolutions for complex problems- Internal cloud solutions ( OwnCloud, NextCloud )- Build and maintain database servers (MySQL, PostgreSQL, Progress) build ODBCconnections between them, write data conversion scripts- Build and manage virtualization systems ( XEN, KVM, Vmware, Proxmox, NAS,ISCSI, NFS)- Backup systems ( Veeam, Bareos, PBS )- Server management (HP, Supermicro, Fujitsu, Dell )- Containerized application management (Docker)- Complex infrastructure management ( Ansible, Puppet ) - Build system management (Gitlab CI/CD)- Atlassian management (Jira, Confluence)- Cloud services management ( AWS , Azure )- End-user support (daily troubleshooting, Onboarding, Offboarding ) - Design automatic desktop installations ( Windows and Linux )- Desktop management implementations silent remote installations etc. (Windows and Linux ) - IT Project management- Implementing generic IT work processes