DMARC (stands for Domain-based Message Authentication, Reporting & Conformance) is a TXT record implenented in a _dmarc subdomain on your DNS server that after DKIM and SPF are implemented ultimatively advises theRead More…
How to implement a SPF record for mail servers
Implementing Sender Policy Framework (SPF) is another mechanism to authenticate your domain as a legitimate mail sender and that means lowering your SPAM score in antispam mechanisms. It is done on theRead More…
Centos VLAN trunking
Centos can accept and easily handle VLAN trunks just as same as doing Access mode. Let’s suppose that you have a WAN interface in access mode (so to say, it’s a plainRead More…
Apache – install a complete web server with SSL
This article will describe how to install Apache on Centos 6.5 and set it up for basic web services, insluding php (with apc), perl, cgi and ruby scripting. Let’s install the pacgagesRead More…
Install OpenVPN on Centos 6.5 (routing mode)
This article will explain how to install OpenVPN on Centos 6.5 (x64) on routing mode. Why routing mode? Well, it consumes less bandwidth than the bridging mode (some call this smaller overhead),Read More…
Blocking torrent with iptables (or any other P2P)
Nowadays, iptables support a so called Layer 7 filtering, which makes things signifficantly easier and more effective whem it comes to blocking torrent with a help of iptablesm or just filtering thoseRead More…
Blocking facebook with iptables (https too)
Some routers can block Facebook (or any other page) with an URL keyword. Yet, this becomes a problem when the page reverts to a secure connection (https). Lately, iptables supports so calledRead More…
Santorini – public transportation explained
It’s very easy to get around in Santorini. There is an efficient and quite simple public solution. So, the facts are: – there is no direct interconnection between the “small” cities (Oia,Read More…
Install OpenDKIM with Postfix on CentOS
OpenDKIM will give Your mail a signature that will eventually lower the spam score of the mail comming from your domain. This will help signifficantly to exclude these mails from being considered as spamRead More…
Amavis-new – bad-header checks tweaking
During the processing of the emails Amavis-new conducts a series of tests, including so called bad-header checks which usually give a headache to system engineers because of false detections (most commonly aRead More…