Software Archives - Server support blog

Category Archives: Software

How to make older Android devices work with Letsencrypt ROOT certificate

How to make older Android devices work with Letsencrypt ROOT certificate 1
The most impacting technical event of the Internet was the expiration of the Letsencrypt DST Root certificate which brought a lot of grief to technical support people and owners of declared obsolete devices. Here is the lists of compatible and incompatible devices provided by Letsencrypt.
There is a way to make some of incompatible devices work, by manually installing ISRG Root X1 Letsencrypt certificate, here is brief instruction for older Apple OS, and below I will show how to do the same on Android 6.0.1 phone.
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Centos7: “ldconfig : Aborted” error and how to deal with it

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On one of my recently installed servers I’ve got customer complain about ffmpeg missing some obscure shared libraries. I went to investigate and met some interesting case
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Tips: How to automate OwnCloud files synchronization on Windows with WinSCP

Tips: How to automate OwnCloud files synchronization on Windows with WinSCP 2
I had a task to automate customer files backup from Windows 10 desktop to NextCloud server. The main idea to keep offline backup that will be updated automatically few times a week (not every day). Main requirement for this was to reduce human interaction with the process as much as possible and exclude some files from backup process all together.
Initially I was not concerned about this – after all there is official Nextcloud Windows desktop client along with command line tool, ownCloud desktop client is also compatible and also has command line tool included, so I thought to myself out of these two I should be able to put together some kind of automation.
Well, to my dismay both official clients proved to be completely useless in unattended automation. Whatever webDAV protocol limitation there were, both command line clients had it, for example simple task of synchronizing single directory, say d:\testsync to remote/testsync was impossible because neither client could create 1st level folder on remote server. It could be underlying limitation or bug of Qt implementation of WebDAV protocol, but figuring that out was out of scope of my task.
I needed reliable and compact (this is not the requirement but always welcome, considering that official clients were dragging with them about 100Mb of Qt core libraries and are useless for my purposes) WebDAV client for Windows with automation and I needed it yesterday.
Then, I discovered that WinSCP supports WebDAV and allows scripting advanced enough to help me with my task.
After some testing I cam up with the following system:

  1. CMD script started by Task Scheduler, executes WiSCP console tool with the script, in the loop until it exits with “success” result

  2. WinSCP console util executes script that synchronizes local storage with NextCloud server

    filemask covers exclusions

This solution synchronizes about 200Gb of data from single Windows every 2-3 days. It’s pretty fast, compact and the best part of it is that it transfers only changed files. Case closed.

sysadmin: cPanel installation script detected MySQL and failed

While trying to install cPanel control panel on just reimaged server I’ve got an interesting error, I’ve never seen before:

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OSX: PPTP VPN networking problem solved with custom MTU

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I had an interesting complain the other day – customer experienced connectivity problems trying to access some web sites while on PPTP VPN connection. The VPN server was running on Linux and also under our control so troubleshooting the situation was pretty easy. All MS Windows based clients didn’t have this problem, only OSX based clients.
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Centos: How to configure DKIM for sendmail on multiple domains

dkim I wanted to configure DKIM for sendmail on multiple domains for one of the dedicated servers and found out that there are no usable instructions for CentOS and few that are available are inconclusive (I will provide the list of information sources at the end of this post). Here is my tested working setup:
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Sysadmin: Why CentOS?

centos_icon Why CentOS as our main server farm Linux distribution? I really want this article to be pure technical, but there are some emotions attached to the question so please forgive me if I might break into rant somewhere down the road.

There were so many times when I was asked by young men with bright eyes and too much free time on their hands “Why do you use Centos for your server farm? Why not (debian,ubuntu, gentoo, insert your favorite distribution here)?” And I am so tired of explaining this decision over and over so I decided to put it together in this article and get it over with once and for all.
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How to revert Mac OSX Leopard to “Welcome” screen: quick recap

Mac-OS-X-welcome-screen-animationSometimes you just need to “start from the the clean slate”. Or pass your old trusted Macbook to your little brother, or even sell it. But you are really not in the mood for reinstalling the OS and don’t even remember where are these OSX DVDs that came with the Macbook about couple of lifetimes ago.
There is a way to reset OSX back to “Welcome” screen wiping out your user account and everything that was in it (not sure about installed application – I think only your personal preferences will go).
The majority information is taken from here – I just summarized it so somebody else or I can find it again when needed.
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