Windows Filesystem

This is a list of noteworthy directories and files on Windows-based operating systems. Note that locations might differ between versions of Windows.

  • C:\Windows\NTDS: On Windows 2008 R2, this is the default location for the Active Directory domain controller database and log files. The location can be on a FAT32 or NTFS partition.
  • C:\Windows\SYSVOL: On Windows 2008 R2, this is the default location for the Active Directory domain controller SYSVOL. Requires NTFS.
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Install Oracle Virtualbox on Linux Mint 17

This is a quick tip on how to install the closed-source version of Virtualbox, currently at version 4.3.16, on a machine with Linux Mint 17.

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Set up an FTP Repository from RHEL DVD

RHEL can be installed from various different sources. One of them is over the network, from an FTP accessible repository. Here's how to create such a repository:

  1. You will first need to install vsftpd from the RHEL DVD. See Install packages from RHEL DVD with yum on how to do that.

  2. After you have installed vsftpd, enable it and start it:

    chkconfig vsftpd on
    service vsftpd start

    At this point, you should be able to open ftp://localhost/ from the same system on which you are working, which will show you the contents of the /var/ftp/pub directory, the default FTP directory on RHEL.

  3. Create a directory for the repository:

    mkdir /var/ftp/pub/rhel
  4. Copy all the files from the DVD to the repository. Assuming that either the DVD or the .iso image is mounted at /media/rhel:

    cp --recursive --archive /media/rhel/. /var/ftp/pub/rhel/
  5. Change the SELinux context of the files in the repository:

    chcon --recursive --reference=/var/ftp/pub/ /var/ftp/pub/rhel/
  6. At this point the repository is only accessible from the system on which it runs, since iptables by default does not allow FTP traffic from other hosts. To open this access, edit your /etc/sysconfig/iptables and add these lines before the COMMIT command:

    -A INPUT -m state --state NEW -m tcp -p tcp --dport 21 -j ACCEPT

    ...and reload the firewall:

    service iptables reload

    Alternatively, you can do from the command line:

    iptables -I INPUT -m state --state NEW -m tcp -p tcp --dport 21 -j ACCEPT
    service iptables save
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Change pptpd port on CentOS

I was testing Point-to-Point Tunneling today, between a CentOS 6 server running pptpd, and some Mikrotik routers as the clients, and I wanted to change the listening port on the pptpd side. After searching and reading a bit of documentation for a while, I was surprised to find that pptpd respects the record for pptp as defined in /etc/services.

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LPIC-2 Revision

My list of topics to revise, before taking the LPIC-2 exam. Note that this list was compiled before the exam objectives' revision in October 2013.


  • Example Servers: bigpie1, sds1, nicds1, officesrv
  • CentOS Install DHCP
  • dhcpd.conf


  • Example Servers: ldap-master, ldap-slave
  • Locate and examine LDIF files
  • ldapadd, slappasswd, ldappasswd, ldapdelete, getent, ldapsearch


  • /proc/sys/net/ipv4/ip_forward and sysctl.conf equivalent
  • RIP with routed


  • iptables chains, default policies
  • flush tables, add rules
  • configure NAT

SSH * Support programs: rpc.idmapd, rpc.mount.d, rpc.nfsd, rpc.statd, portmap * Setting up exports with NFS in /etc/exports, and on the fly with exportfs * showmount, nfsstat, rpcinfo * Mount over NFS

FTP * PAM Basics, PAM Stacks, Examples of PAM Modules * PAM Configuration, NSS Configuration

TCP Wrappers

  • /etc/hosts.allow, /etc/hosts.deny
  • Calling TCP Wrappers from /etc/inetd
  • /etc/xinetd


  • Network Design for SNORT


  • Fail2Ban configuration


  • Identifying active bootloader on a system (based on files on disk or with bootinfoscript)
  • LILO Error Messages
  • GRUB Legacy Error Messages
  • GRUB2 Error Messages and Rescue Console

Boot Time Troubleshooting

  • initrd
  • dmesg
  • /etc/inittab, runlevel, SysV and Upstart

Hardware Troubleshooting

  • Hardware detection (/proc/cpuinfo, lspci, lsusb, lsdev, lsmod)

Log files Troubleshooting

  • Helpful files: syslog, messages, dmesg or boot.log, secure, cron, lastlog
  • Scanning Log Files with head, tail, less, grep, logcheck
  • syslogd configuration
  • Logrotate configuration

Software Troubleshooting

  • strace and ltrace, ldd, lsof, strings
  • Library Dependencies
  • Kernel options in /proc/, sysctl, /etc/sysctl.conf
  • init and the process tree
  • top

Troubleshooting Login and Accounts

  • Logins with login, XDM, KDM, GDM, getty
  • Network Logins with Telnet, SSH, X, XDMCP, VNC
  • Users management with usermod
  • Login variables in /etc/login.defs, /etc/profile, /etc/bashrc, ~/.profile, ~/.bashrc


  • Schedule Jobs with Cron


This is a random list of filesystems.

  • zfs
  • btrfs
  • xfs
  • ext2
  • ext3
  • ext4
  • GlusterFS
  • MooseFS
  • Ceph
  • Lustre
  • Fraunhofer Parallel Cluster File System (FhGFS)
  • DRBD

Hello, I'm Marios Zindilis and this is my website. Opinions are my own. You also find me on LinkedIn and GitHub.

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