Aleksandar S.

More than 20 years of working experience in networking and server administration. Administering and scripting networking applications, database applications, web applications and internet & intranet servers In position of expert engineer for networking infrastructure, IT security expert and senior linux/windows/OSX administrator In charge of designing of LAN/MAN/WAN networking infrastructure, designing and implementation of fiberoptic backbone and copper networking installation. Administration of linux servers and networking devices (switches, routers, firewalls, NAS) am in charge of more than 150 linux servers, both physical and virtual Working with L2/L3 switches, routers, firewalls, NAS devices, switching&routing protocols (RIP, OSPF, SNMP, IGRP/EIGRP, VTP, BGP). Certified Cisco and Mikrotik networking engineer. OS platforms - Red Hat/Centos, Debian/Ubuntu, Gentoo, OpenSolaris, BSD flavors, Windows, OSX Server. Networking equipment - Cisco, HP, Mikrotik, ZTE, Huawei Some of the open-source technologies and daemons I have experience with: - bash, perl and python scripting - apache/nginx web servers (standalone, or in backend mode for tomcat, with one or many virtual hosts) - mysql/postgresql database installation and administration - squid (with or without dansguardian+clamav as content filter/realtime AV) - cloud (openstack, AWS, Azure, gcloud, OVH, rackspace, digital ocean....) - snort (with BASE and Snorby as web GUI) and suricata IDS - iptables (with or without web GUI) - BIND (standalone or master/slave) - postfix (as MTA, combined with alot of different tools such as spamassassin, amavis, clamav, roundcube, postfixadmin, dovecot, cluebringer, mailgraph) - zenoss, zabbix and cacti (with plugins and OUIs) - dovecot (as pop3/imap server of choice, combined with postfix and amavis, clamav, roundcube, postfixadmin, spamassassin) - amavis (with alot of customized settings for things such as double AV scanning, DKIM support, catching of spam headers...) - spamassassin (standard and heuristic bayesian analysis, fine tuning of scoring, OCR integration, SPF integration....) - ClamAV (using both standard and unofficial virus definitions, making of 0-day virus signatures caught in the wild...) - freeradius (with MySQL backend for AAA) - samba (in all possible variatons - standalone simple CIFS sharing, member of windows AD, standalone AD controller, one of the controllers in windows AD) - pureftpd, vsftpd and proftpd (as standalone servers or with virtual users) - xen, vmware, hyperv and kvm virtualization (stock or Xenserver/Proxmox distributions) - asterisk (via Elastix linux distribution) - roundcube as preferred web-mail interface (with alot of customized plugins) - openmediavault/openfiler linux distros for NAS - HA clustering (failover based on DRBD and heartbeat/pacemaker+corosync) - NUT (daemon for UPS monitoring and controlling) - openvpn (with various configurations and backends) - pptp vpns (with various configs and backends) - all kind of linux distributions - RH, CentOS, openSuSe, Debian, Ubuntu, Gentoo, Arch.... - hardening of linux distributions (iptables, fail2bain, allow/deny mechanism, AIDE, SELinux, AppArmour, occasional pen testing) - puppet automation - rancid (centralized backup of config files) - bacula, urbackup and rsync backup