Monthly Archives: September 2017

Sysadmin: How to configure PXE server on VMware workstation

Posted by on 09/20/2017 No comments

Vmware Workstation is the perfect candidate for configuring local PXE server for testing and development – it contains independent DHCP server that is an equivalent to ISC DHCP v2. All you need is to have your own VM that will be serving as TFTP server for network boot images, there are plenty of instruction on how to do that on Linux (.
I decided to configure my Vmware workstation for windows (windows 7 in that case) DHCP as PXE server using vmNAT network adapter, since I already have Linux VM in vmNAT network which I can configure for TFTP server.
The config file is %SYSTEMDRIVE%\Users\All Users\vmnetdhcp.conf, in order to enable PXE you will need to add 4 lines.

  1. 2 Lines at the top right after comments
  2. And another 2 lines inside the subnet block that is related to your VmNAT adapter network

    You will need to assign static IP to your Linux TFTP server so that network booted VMs will be able to access it.
  3. Now you can go to Administrative tools->Services and restart Vmware DHCP server – if everything correct then it will restart without complains.
  4. In order to configure your TFTP server use this, or this instruction

Sysadmin: How to install Letsencrypt on CentOS

Posted by on 09/18/2017 No comments


Since Letsencrypt started their services life became much easier (or less). You can get free valid and secure SSL certificates that are recognized by majority of browsers, but for that you need to do some initial configuration and keep in mind that if you don’t renew all these nice certificates will turn into pumpkin after 2 month.
Here is the one liner command to install certbot-auto in CentOS 6 (requires additional Python 2.7 from EPEL repo)

Almost, the same for the CentOS 7 just without Python.

Here is how quickly request/retrieve certificate for your website on domain.com that is hosted under /home/domain/public_html from command line (presuming that the site is answering on this server already e.g. DNS and web server configured properly)

If the request was successful your new certificates could be accessible from /etc/letsencrypt/live/domain.com, where
privkey.pem – is the certificate key, cert.pem – bare certificate fullchain.pem – certificate along with the whole CA chain.
Don’t forget that these are valid for 2 month only. You’ll need to run

after that to get valid certificates.