Essential Linux tools for system admins. Security, firewalls, control panels, email servers etc.
rkhunter – the Rootkit Hunter helps to find something what shouldn’t be living in your system.
chkrootkit – locally checks for signs of a rootkit.
Lynis – performs an extensive health scan of your systems to support system hardening and compliance testing.
John the Ripper – Open Source password security auditing and password recovery tool.
LMD – Linux Malware Detect malware scanner.
REMnux – is a Linux toolkit for reverse-engineering and analyzing malicious software.
Project Freta – Detects novel malicious software, kernel rootkits, process hiding, and other intrusion artifacts via agentless operation by operating directly on captured VM snapshots.
CSF & LFD – Lovely pair of A Stateful Packet Inspection (SPI) firewall and Login/Intrusion Detection and Security application for Linux servers.
Iptables – Iptables and ip6tables are used to set up, maintain, and inspect the tables of IPv4 and IPv6 packet filter rules in the Linux kernel.
Pfsense – pfsense is a free and open source firewall and router that also features unified threat management.
Nothing beats command line, but in many situations control panels offer easier way to perform tasks. That is especially true what comes to hosting clients who want get essentials things done without touching Putty. Here are my favorite three panels. Each is aimed a bit different users, but generally you can do everything you can imagine and a lot of more with each.
Cpanel/WHM – paid control panel, but comes free with many web hosting plans as well as reseller hosting plans. Possible the most well known control panel. Cpanel handles account level tasks while WHM gives control over resources, making them together one of the best solution for example reseller hosting.
Plesk – paid control panel, but comes free with many shared web hosting plans. Aimed especially for WordPress users, but works also as a general web hosting control panel. Extremely useful for WordPress hosting thanks to handy extensions such as WP-Toolkit and it’s Smart Updates.
Control Web Panel – previously known as CentOS Web Panel or CWP, free and paid versions with everything you need. They offer advanced features such as file lock and secure kernel, not to mention integrated CSF / LFD manager and many other useful things. Prefect for example running virtual server.
Email servers & security
Email servers are essential for most organizations and businesses. A lot of companies have outsourced their emails to big corporations. That might be fine, but it might be privacy issue as well as expensive compared to own email server. However, running email server is not necessary an easy task. Here is my favorite email servers for Linux systems.
Zimbra – email server is available as a community (OSE) edition and as a paid enterprise edition. Handles anything from one node and email account to multiple nodes and tens of thousands of accounts. Supports SMTP(S), IMAP(S), POP3(S), SSL/TTL and comes with webmail, file sharing, task lists, contact lists etc. Works perfectly with Outlook, MacMail and Thunderbird clients. Requires advanced administration at setup stage as well as later, managed Zimbra email server is a good option, if you do not have time to inside Zimbra’s inner secrets.
IredMail – Works on Red Hat, CentOS, Debian, Ubuntu, FreeBSD, OpenBSD.
clamav.net – open source antivirus engine for detecting trojans, viruses, malware & other malicious threats.
Proxmox Mail Gateway – leading open-source email security solution helping you to protect your mail server against all email threats.
Proxmox VE – Proxmox Virtual Environment is an open source server virtualization management solution based on QEMU/KVM and LXC.
KMV – Kernel-based Virtual Machine is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V).