The RaspberryPi and many similar single-board computers do not have an RTC or “Real Time Clock” and without internet connectivity cannot retain their time setting. Therefore most RaspberryPi Linux-distributions employ NTP to sync the time right after boot. If you are not able to use an internet connection and therefore no NTP, but have a GSM modem or phone and a valid sim card at hand, this guide may be suitable for your needs.
Continue reading Sync time on Linux via GSMSecuring the RabbitMQ Management Console with SSL before version 3.7.10
This article was previously posted on gettingcirrius.com, a blog of Richard Clayton, who released it under Attribution 3.0 Unported (CC-BY 3.0). His old blog recently went offline, therefore I am reposting this useful how-to on setting up SSL for the RabbitMQ management console.

This is an article in the RabbitMQ Configuration and Management Series. For more articles like this, please visit the series’ index.
Continue reading Securing the RabbitMQ Management Console with SSL before version 3.7.10Change Plesk spam-settings in bulk
Since Plesk per default uses the static userdb-driver of Dovecot, it may seem difficult to easily iterate through all mailboxes on the server, for example in order to change the spam-settings of all mailboxes on the systems at once while keeping the “individual settings per-mailbox” functionality enabled.
The following one-liner may be helpful in such case:
while read domain; do (while read user; do plesk bin spamassassin --update $user@$domain -status true -personal-conf true -action move -hits 6; done < <(ls -1 /var/qmail/mailnames/$domain)); done < <(ls -1 /var/qmail/mailnames/)
In this case, the domains and mailboxes are placed in/var/qmail due to a previous upgrade from qmail to Dovecot. If the directory in your case differs, make sure to change it in the one-liner, too.
List number of requests from specific IPs from Nginx access-Logs
less access.log | awk '{print $1}' | sort | uniq -c | sort -n | tail
Deny in iptables based on AS-number
iptables -N AS_DENY; iptables -I INPUT -j AS_DENY; whois -T route -i origin AS57169 | grep '^route:' | awk '{print $2}' | aggregate -q | xargs -n1 -I% iptables -A AS_DENY -s % -j DROP
Search for entrys containing a specific string
SELECT * FROM `Liste` WHERE Webseite LIKE '%http:// http://%%'
//the string in this case is "http:// http://"