Linux
Generate a CSR (Certificate Signing Request) on your server when you want to get a certificate from a certified provider is often a mandatory step, very easy to execute. Here are the different steps to execute: 1. Create a specific directory where you will put all your filesmkdir sub.domain.
Linux
It can happen that you're getting that message when trying to connect to your linux server: You are required to change your password immediately (password aged) WARNING: Your password has expired. You must change your password now and login again! Changing password for user mylinuxuser. (current) UNIX password:
Linux
If you're getting many "unstrusted issuer" alerts in your app logs, it might be due to some CA trusted certificates outdated. To fix that, just perform an update: For Ubuntu/Debian update-ca-certificates For CentOS/RedHat update-ca-trust extract
Linux
If you need to push multiple lines to one file through a bash script, you can simply use that syntax: cat > /etc/ntp.conf << _NTPconf_ server 1.2.3.4 server 5.6.7.8 _NTPconf_ Tip: Be aware that if you're using indentation, last
Linux
There's no easy way to list all the IPs connecting to your postfix server for sending mail. But you can easily extract them from all your postfix logs. For our example, we will consider the logs from postfix to be as default and located in /var/log/maillog
Linux
It's possible to connect to serial console with MacOS without using a specific app but only screen. First, you need to find the correct device you will use to connect to the serial console. Depending on your installation and your adapter, you'll can find it under
Linux
When you're facing performance issues, it's always useful to check CPU/MEM usage per process to see if you have an issue with a specific process. For that, you can use ps and some sorting commands. Tip: You can shrink the results to the first lines
Linux
Here is a simple script with configuration file to generate a self-generated SSL certificate (cert/key pair). First define a config file openssl.cnf containing the certificate informations: [ req ] default_bits = 2048 encrypt_key = yes distinguished_name = req_dn x509_extensions = cert_type prompt = no [ req_dn ] # country (2
Linux
You can get standard information about the certificate directly by opening a connection to a website: openssl s_client -showcerts -connect python.org:443 </dev/null Answer will be like: CONNECTED(00000003) depth=3 C = SE, O = AddTrust AB, OU = AddTrust External TTP Network, CN = AddTrust External CA Root
Linux
You already probably noticed that if you want to update the ownership of a symbolic link on any UNIX system, a simple chown won't do the job. Indeed, let's suppose you have this: 8 lrwxr-xr-x 1 user1 group1 4 Jun 13 23:46 link
Linux
It's not easy to perform bulk DNS resolution when you have many DNS/IPs to control. Here is a simple script allowing you to perform DNS resolution over a list of DNS entries or IPs. Here is a list of DNS (names and IPs) that we put in
Linux
There is no easy way to remove a list of mails in queue with a same sender or domain in Postfix. But you can use some standard commands to get this working. First check the list of mails you want to remove with something like postqueue -p |grep -e '