ServerBuddies Support Blog

How to check Apache Modules Switched Off in VPS-Optimized Mode

The list of the modules can vary depending on the operating system distribution and architecture. When Parallels Plesk Panel is installed and the optimized mode is switched on, you can check the list in the following files:

* On 32-bit operating systems -

* On 64-bit operating systems -

Turning the VPS-Optimized Mode on

If you deploy Parallels Plesk Panel into VPSes other than Virtuozzo-based (Parallels Virtuozzo Containers or OpenVZ containers), consider switching the Panel to a special mode of operation - optimized for virtual environments. The mode switches off modules that are not critical for hosting services. This makes the Panel use less memory than other control panels available on the market, which ensures better utilization of hardware resources and increased density of virtual environments per server.

* During the installation, the Panel requires more RAM than it utilizes in the VPS-optimized mode.
* Since Parallels Premium Antivirus and Spamassassin are memory-consuming applications, it is not recommended to install them if you require a high VPS density.
* It is not possible to turn the VPS-optimized mode on if Customer and Business Manager is installed.

Important: The VPS-optimized mode can be turned on only before the Panel initialization (aka initial configuration).

To turn the VPS-optimized mode on, run the following command:

Redhat Rescue Mode

Rescue mode provides the ability to boot a small Red Hat Enterprise Linux environment entirely from boot media or some other boot method instead of the system’s hard drive.

There may be times when you are unable to get Red Hat Enterprise Linux running completely enough to access files on your system’s hard drive. Using rescue mode, you can access the files stored on your system’s hard drive, even if you cannot actually run Red Hat Enterprise Linux from that hard drive. If you need to use rescue mode, try the following method:

Using the CD-ROM to boot an x86, AMD64, or Intel® EM64T system, type

at the installation boot prompt. Itanium users should type elilo linux rescue to enter rescue mode.

If a network device is in promiscuous mode, the kernel will receive all network traffic (i.e., the CPU load will increase). Then the latency of network responses will also increase, which can be detected.
promisc mode is a configuration of a network card that makes the card pass all traffic it receives to the central processing unit rather than just frames addressed to it — a feature normally used for packet sniffing.

Each frame includes the hardware (Media Access Control) address. When a network card receives a frame, it normally drops it unless the frame is addressed to that card. In promiscuous mode, however, the card allows all frames through, thus allowing the computer to read frame intended for other machines or network devices.

Many operating systems require superuser privileges to enable promiscuous mode. Ifconfig command can be used to enable this mode

Enable passive mode for FTP in Plesk Panel

Log in as “root” to the server shell over SSH.

Edit your ProFTPD configuration file.

1. Issue the command vi /etc/proftpd.conf
2. Add the following lines anywhere within the [Global] section:

3. Save the file

Log in to Parallels Plesk Panel as “admin”, go to Modules > Firewall, and click Edit Firewall Configuration.

Click Add Custom Rule.

Specify the following:

1. Rule name
2. Direction: select Incoming.
3. Action: select Allow.
4. Ports: in the Add port input box, enter the value 49152-65534. Leave the TCP option selected, and click Add.
5. Click OK.
6. Click Activate, and then click Activate again.