| Security – Error installing Kali: “Installation step failed” |
When I was installing a Kali virtual machine, I came across an error in the “Software selection” step
After confirming the software, the installation shows an “Installation step failed” message.
After browsing through some sites and forums, apparently the problem could be related to not configuring enough space and a suggestion is configuring more than 30-40 GB. But no luck, … Read more
| Linux – rsyslog: parsing and splitting message fields |
Until now I hadn’t used the options and features rsyslog comes with. Let me show a simple example I have done today. This is an example log line rsyslog has received from iptables (I have configured iptables to log certain connections attempts to identify and save devices with malware):
Sep 29 15:30:39 myserver kernel: [malware3] IN=ens192 OUT=ens192 MAC=XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX SRC=10.15.13.17 |
| Linux – Simple DNS server using DNSmasq |
This article offers a 5 min howto about configuring your own DNS server (perhaps for your company or maybe for your home network) using DNSmasq. Obviously, only the surface is covered on this post.
Given my router does not allow me to add host entries for local DNS resolution, I decided to use DNSMasq on one of my internal network … Read more
| Icinga – Notification template with notes support |
I have just configured an Icinga2 notification template for hosts and services to replace the ugly and impractical default one.
Not big things but useful in my opinion
UTF Icons are included depending on the state of the host or service
This notifications scripts can include … Read more
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| Icinga – Notes section in markdown language |
Not sure since what version this feature is available but I have started to use the notes section of the services i am monitoring in Icinga in markdown syntax.
icingaweb2 package version 2.6 that is compiled for Debian 10 (Buster).
Package: icingaweb2
Version: 2.6.2-3You may think you do not need it for, but in my humble opinion it is … Read more
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| Linux – SQL Server command line to perform queries (mssql-cli) |
There are different methods to run queries against an SQL Server from a Linux machine. The one I am using is mssql-cli (https://github.com/dbcli/mssql-cli)
As you can check in the related github website, it has the following features:
It has been packetized for a lot of distributions … Read more
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| Linux – Show git branch in bash prompt |
If you are a Git user, you can find very useful this custom prompt.
Shows working branch when it detects the current folder is a git one:
user1@labdebian ~/data $
user1@labdebian ~/data $ cd ../myproject/
user1@labdebian ~/myproject (master) $user1@labdebian ~/myproject (master) $ git checkout -b branch1 Switched to a new branch 'branch1' user1@labdebian ~/myproject (branch1) $ user1@labdebian ~/myproject… Read more
| Nextcloud – Error modifying files or folders: locked error |
Yesterday I came across a problem in which I tried to modify (rename, delete, …) a folder and it returned an error.
Nextcloud logs (/var/www/nextcloud/data/nextcloud.log) showed the following:
"reqId":"Pf4KW9q1WDVe1YdmG0Mt","level":3,"time":"2019-09-10T16:36:53+00:00","remoteAddr":"63.223.129.127","user":"user1","app":"no app in context","method":"DELETE","url":"\/remote.php\/dav\/files\/user1\/ALBUMS\/New%20folder","message":{"Exception":"OCP\\Lock\\LockedException","Message":"\"files\/8010dab5adf49336ecdaf75a2008d5ab\" is locked","Code":0,"Trace":[{"file":"\/var\/www\/html\/nextcloud\/lib\/private\/Files\/Storage\/Common.php","line":779,"function":"changeLock","class":"OC\\Lock\\DBLockingProvider","type":"->","args":["files\/8010dab5adf49336ecdaf75a2008d5ab",2]},{"file":"\/var\/www\/html\/nextcloud\/lib\/private\/Files\/Storage\/Wrapper\/Wrapper.php","line":615,"function":"changeLock","class":"OC\\Files\\Storage\\Common","type":"->","args":["Nueva carpeta",2,{"__class__":"OC\\Lock\\DBLockingProvider"}Enter maintenance mode
sudo -u www-data php occ maintenance:mode --on
Then, all entries of the table oc_file_locks … Read more
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| Security – List available cipher suite using nmap |
If you are in process of securing your web server or site, there are some tools and online resources that can help us a lot (in one of the following posts will show you some of them).
But simply using the command the fantastic nmap tool, another interesting feature is listing the available cipher suite certain site offers using the … Read more
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| Security – View HTTP headers using tcpdump |
If you need to trace the HTTP request and response headers by capturing the related packets, you can use tcpdump in this way:
tcpdump -i ens192 -A -s 10240 'tcp port 80' | grep -v IP | egrep --line-buffered "..(GET |\.HTTP\/|POST |HEAD )|^[A-Za-z0-9-]+: " |sed -r 's/..(GET |HTTP\/|POST |HEAD )/\n\n\1/g'
For example, filtering tcp port 80 and 192.168.10.100 IP address:… Read more
