Linux

It seems that ISPConfig3 checks for entropy availability to be below 200 and also 400 per the following file, /usr/local/ispconfig/server/bind_plugin.inc.php. Line 93 and line 210 check for entropy availability. Line 93, inside function soa_dnssec_create(): if (file_get_contents(‘/proc/sys/kernel/random/entropy_avail’) < 400) { $app->log(‘DNSSEC ERROR: We are low on entropy. Not generating new Keys for ‘.$domain.’. Please consider installing…

Took me a minute to figure this out but it works. Given the following string, I want to replace { and } with [ and ] keeping each number inside and only with a number inside the braces without space and without letters. data.txt: {1}: Today is tomorrow’s yesterday. {2}: This year is next year’s…

I’m not sure why systemd doesn’t remove the service, but to do so you can run through the following commands. Also check /etc/init.d/[servicename] as there may be a wrapper there as well. If you know what service you’re looking to remove, great. If not, you can quickly find all the systemd services enabled on your…

Input Validation Whitelist Protection Cacti Data Input methods that call a script can be exploited in ways that a non-administrator can perform damage to either files owned by the poller account, and in cases where someone runs the Cacti poller as root, can compromise the operating system allowing attackers to exploit your infrastructure. Therefore, several…

To test SMTP auth with StartTLS, I used the following method. Base64 encode the username and password. echo -ne “yourpassword” | base64 eW91cnBhc3N3b3Jk echo -ne “your@email.com” | base64 eW91ckBlbWFpbC5jb20= Connect to the SMTP server using the openssl client. openssl s_client -connect smtp.test.com:587 -starttls smtp -crlf Once connected to the mail server, identify myself with EHLO…

I have an old Lenovo Yoga 2 (i5-5400u, 4GB RAM, 128GB SSD). This 2-in-1 system does not have an ethernet port and during Debian installation using the netinstall ISO, non-free firmware is needed for the Intel wireless controller. I went to Debian’s installer page for non-free firmware (for Bullseye) and downloaded the zip file: https://cdimage.debian.org/cdimage/unofficial/non-free/firmware/bullseye/11.3.0/…

By default, Zentyal creates a Home Folder for each user created through the web interface and not through Active Directory Users & Computers (dsa.msc). To disable this action, modifying the Samba stub for Zentyal is the preferred method. In order to maintain the changes across Zentyal and Samba updates, a Samba stub should be copied…

Some notes on increasing LVM partition in Linux. Terminology Physical Volume (PV): This can be created on a whole physical disk (think /dev/sda) or a Linux partition. Volume Group (VG): This is made up of at least one or more physical volumes. Logical Volume (LV): This is sometimes referred to as the partition, it sits within a volume…

grep -E -o “[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+.[A-Za-z]{2,6}”