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Install XRDP in Debian 9

August 8, 2018 by Rumi

Install XRDP and TigerVNC server

$ sudo apt install -y xrdp tigervnc-standalone-server

Connect XRDP from Windows 10

Windows start button -> Windows Accesssories -> Remote Desktop Connection

Input FQDN or IP address of XRDP server and connect to XRDP.

XRDP RDP terminal will appear. Select “XVNC” Session and connect.

Create a Linux Router with DHCP services

August 5, 2018 by Rumi

It’s pretty easy to build a Linux router even on a virutal machine. I’ve used virtualbox to create a LAN NAT router with DHCP services using webmin. However, I’m not going to cover on how to use a virtualbox VM 🙂

Let’s create the NAT Router first.

On Webmin go to Networking > Network Configuration > Routing and Gateways

Fig-1

Select right ethernet interface on Default Route
Fillup the correct gateway
Enable “Act as a Router”

On Networking > Linux Firewall > Select “Reset Firewall”

Install wkhtmltopdf on Debian 8, 9

January 18, 2019August 3, 2018 by Rumi

Installation on Debian 8

apt-get update
aptitude install xfonts-base xfonts-75dpi fontconfig xvfb
mkdir ~/src/wkhtmltopdf -p
cd ~/src/wkhtmltopdf
wget https://bitbucket.org/wkhtmltopdf/wkhtmltopdf/downloads/wkhtmltox-0.13.0-alpha-7b36694_linux-jessie-amd64.deb
dpkg -i wkhtmltox-0.13.0-alpha-7b36694_linux-jessie-amd64.deb
echo 'xvfb-run --server-args="-screen 0, 1024x768x24" /usr/local/bin/wkhtmltopdf $*' > /usr/bin/wkhtmltopdf.sh
chmod a+rx /usr/bin/wkhtmltopdf.sh
ln -s /usr/bin/wkhtmltopdf.sh /usr/local/sbin/wkhtmltopdf
/usr/local/sbin/wkhtmltopdf https://www.google.fr output.pdf

Installation on Debian 9

Find Ethernet Connection Speed

July 29, 2018 by Rumi

Type the following command to get speed for eth0:

$ ethtool eth0 | less

$ ethtool eth0 | grep -i speed

You can also use the following two commands:

$ dmesg | grep eth0 | grep up
$ dmesg | grep bond0 | grep up

OR use the command line utility called mii-tool to checks or sets the status of a network interface’s Media Independent Interface (MII) unit:

$ mii-tool -v eth0

Src: https://www.cyberciti.biz/faq/howto-determine-ethernet-connection-speed/

Installing Let’s Encrypt on a Zimbra Server

June 15, 2018 by Rumi

Let’s Encrypt must be installed on one Linux machine to obtain the proper SSL Certificate, CA Intermediate, and Private Key. It is not required that it be on the same Zimbra Server, but it could save time and help to obtain the renewals, etc.

First Step is to stop the jetty or nginx service at Zimbra level

zmproxyctl stop
zmmailboxdctl stop

Second step is to Install git on the Server (apt-get install git/yum install git), and then do a git clone of the project on the folder we wantNote: On RedHat/CentOS 6 you will need to enable the EPEL repository before install.

git clone https://github.com/letsencrypt/letsencrypt
cd letsencrypt

Let’s now run Let’s Encrypt in auto mode and use the certonly option, because for now the project can’t automatically install the cert on Zimbra servers.

root@zimbra86:~/tmp/letsencrypt# ./letsencrypt-auto certonly --standalone

If you need to have multiple hostnames on the same SSL, so a Multi-SAN, SSL, please run instead, where -d are your domains:

root@zimbra86:~/tmp/letsencrypt# ./letsencrypt-auto certonly --standalone -d xmpp.example.com -d conference.example.com

Bind DNS Auto Slave Using Webmin

June 13, 2018 by Rumi

The latest webmin has bug! In this tutorials I’m using webmin verison 1.801- that actually works. Don’t know if webmin team really knows are aware of the bug 🙁

So, let’s start. But before that, it’s assumed that you have webmin installed in both the servers.

Configuring Webmin Server

Best free bandwidth monitoring software and tools to analyze network traffic usage

June 13, 2018 by Rumi

To keep an eye on the health of your network and diagnose problems that crop up, an essential activity is monitoring your bandwidth and knowing which traffic is consuming it.

Your ISP promises to provide you with a reliable pipe to the Internet of a certain volume; your chosen network hardware install is designed to provide a particular level of service within your facility. Are you getting your expected bandwidth and availability, or is something failing to deliver? Is there unexpected traffic consuming the bandwidth that you are getting?

Tools to monitor bandwidth can leverage various traffic-monitoring technologies. A host can observe all the packets passing by a particular network interface (that is, packet capture). Most managed network devices – and hosts – support SNMP, and so they can be queried to get performance statistics. If your network devices support a traffic monitoring protocol like NetFlow or sFlow, they can publish traffic data to your monitoring tool.

Which bandwidth monitoring tooling is right for you? There are several considerations. One factor is what monitoring technologies your installed hardware supports (eg, do they support SNMP? NetFlow? sFlow?). One is the size and complexity of your network; a simple tool that’s a great fit for a small office is completely inadequate for a large sophisticated network. Here we’ll look at the most popular and feature-rich free bandwidth monitoring tools.

Here’s a list of the best free bandwidth monitoring tools:

SolarWinds Real-Time Bandwidth Monitor
WhatsUpGold
SoftPerfect NetWorx
Manage Engine Bandwidth Monitor
PRTG
ntopng

Enable WIndows Photo Viewer in Windows 10

June 13, 2018 by Rumi

Default windows “Photo” app is clumsy at some point, missed the earlier “Photo Viewer” program. So, going back to root and after googling, here’s a small hack to enable “Windows Photo Viewer” in windows 10 edition.

Download the photo.zip and unzip it. You’ll get a photo.reg file. The file is created from this forum http://www.tenforums.com/software-apps/8930-windows-photo-viewer-gone-2.html#post290818
Double-click on your new REG file to merge it with your Windows Registry. You will need to click through the User Account Control and a few other windows to allow the file to make changes to the Registry.
Basically you are done.
Next what you need is to right click on any JPEG/JPG/BMP/PNG/GIF file that you want open/view using legacy windows photo viewer and make it as default.

Zimbra send http traffic to https or keeping both in mix

June 10, 2018June 10, 2018 by Rumi

HTTP proxy can support protocol modes for HTTP or HTTPS only, both HTTP and HTTPS, mixed HTTP and HTTPS or HTTPS redirect from HTTP. Redirect is a popular configuration. This configuration must be made to the proxy servers.

HTTPS redirect from HTTP

zmprov ms proxy.server.name zimbraReverseProxyMailMode redirect

HTTP and HTTPS (support both)

zmprov ms proxy.server.name zimbraReverseProxyMailMode both

HTTPS only

zmprov ms proxy.server.name zimbraReverseProxyMailMode https

HTTP only

zmprov ms proxy.server.name zimbraReverseProxyMailMode http

“mixed” will cause only authentication to be sent over HTTPS

zmprov ms proxy.server.name zimbraReverseProxyMailMode mixed

Src:
https://wiki.zimbra.com/wiki/Enabling_Zimbra_Proxy_and_memcached#Protocol_Requirements_Including_HTTPS_Redirect

Mount CD or DVD Rom in Linux

June 3, 2018 by Rumi

Finding out your CD/DVD names in Linux

Use the following command to find out the name Of DVD / CD-ROM / Writer / Blu-ray device on a Linux based system:

# lsblk

# dmesg | egrep -i --color 'cdrom|dvd|cd/rw|writer'

Sample outputs (/dev/sr0):

[ 5.437164] sr0: scsi3-mmc drive: 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray
[ 5.437307] cdrom: Uniform CD-ROM driver Revision: 3.20

Syntax to mount DVD / CDROM in Linux
The syntax is:

# mount -t iso9660 -o ro /dev/deviceName /path/to/mount/point

Create a mount point, type mkdir command as follows:

# mkdir -p /mnt/cdrom