Ubuntu 24.04 We all sync our agendas. It means that your calendar is synchronized with a server and, probably, from the server synchronized with another client. So your laptop is in sync with your phone etc. I was looking, however, for a tool to sync my Apple iCloud calendar with a calendar on my private SOGo-account (with CalDAV support). So in this respect 'syncing' means keeping two different agendas the same. A simple way to do this is OneCal. But I don't want to share my credentials or c...

Ubuntu 24.04 | Mailcow 2025-10 | Rspamd 3.13.2 In my mailcow logs I stumbled upon a lot of errors on downloading maps files from maps.rspamd.com, most of the time like: map; http_map_error: error reading https://maps.rspamd.com/freemail/free.txt.zst(157.180.118.77:443): connection with http server terminated incorrectly: ssl connect error: syscall fail: Connection refused or map; http_map_error: error reading https://maps.rspamd.com/rspamd/surbl-whitelist.inc.zst(157.180.118.77:443): connecti...

Ubuntu 24.04 Many mail servers make use of ClamAV. ClamAV is an open source (GPLv2) anti-virus toolkit, designed especially for e-mail scanning on mail gateways. Default configuration is to check for updates on database.clamav.net. This is often defined somewhere in the UI or in a config file named freshclam.conf. As of result of rate limiting by clamav.net client IP's can be greylisted. I've seen configurations where clients check every minute (!) so it is understandable this greylisting occu...

Ubuntu 24.04 Setting up a webserver is quite straightforward. 1- install nginx apt update apt install nginx -y 2- create and open config file vi /etc/nginx/conf.d/mydomain.conf 3- paste this into the config file server {   server_name mydomain.com; // your FQDN here   root /opt/www; // root path of the webserver   location / {   }   listen [::]:80; // delete if you don't have ipv6   listen 80; } 4- start webserver and test systemctl restart nginx Open http://mydomain.com in your browser ...

Ubuntu 24.04 Setting up a proxy server is quite straightforward. Suppose you have some web service running on port 8008. From the local machine it is accessible by http://localhost:8008. We'd like to have it accessible from outside, secure (https) and on the default port 443. Installation and configuration is similar to a regular webserver. Replace step 3 with this one: 3- paste this into the config file server {   server_name mydomain.com; // your FQDN here   root /opt/www; // root path of...