Check Mail Server Certificate with openssl
You applied a new certificate to you mail server. Now you want to know, if the right certificate with the matching chain is used: openssl s_client -starttls smtp -showcerts -connect…
How to split DNS DKIM records
DNS TXT records do have a limitation. Strings must not be longer than 255 Bytes. This limitation can hurt you with SPF records or DKIM records. In this case you…
Show open ports on Mac
If you want to know which ports are open on your Mac, you can use built-in tools in terminal: lsof -i -P | grep -i "listen" This gives you a…
Create a Centos Repository Mirror
Quite a few companies do not allow direct connections from the internal servers to the Internet. This is usually no problem, beside the time, when you want to update your…
Using Apple Mac Keyboard with Ubuntu
You are a Mac user and run Linux machines virtually on your Macbook or your console keyboard is an Apple Mac Keyboard. Ubuntu Linux sets the keyboard parameters in the…
Fortigate Firewall Command Tree
If you want to know which commands exist on a FortiGate, type tree on the command line. You get the whole command structure of the installed operating system. config antivirus…