Postfix Outbound SPF Checker Idea

While working on figuring out a way to block email sent to and from external users, without blocking email to or from internal domain and allowing relay…. I had this idea:  What if I could check the SPF record of a domain when checking the from header of a domain.  This would allow me to dynamically permit emails from any Continue reading Postfix Outbound SPF Checker Idea

IPv6 OpenVPN Tunneling with Asus MerlinWRT and Postfix Smarthost over v6 Tunnels

Hey All, It’s been a while and I finally got around to updating my postfix cluster to send email over my OpenVPN tunnel with standard ports to my local zimbra server instead of using a non-standard port over the wan.  While I was at it, I figured I’d trying pushing IPv6 and here’s how that went.  A little backstory, my Zimbra Continue reading IPv6 OpenVPN Tunneling with Asus MerlinWRT and Postfix Smarthost over v6 Tunnels

Get IP Address of client without web scripts (like php)

Figured I’d do a quick post about this, I had the need to show my IP address (like https://www.icanhazip.com/ but internal).  I didn’t really feel like adding php to my existing nginx server, so here’s what I did. First) I create a new virtual-host with the internal server-name (or ip) of my nginx server, new document root of “ip” and a Continue reading Get IP Address of client without web scripts (like php)

Not all technical blog posts are created equal.

The internet is the second source of opinions (first being Politicians). But what does that have to do with Technical Blogs? Recently I embarked on a security focused project of adding 2 Factor authentication to the some network authentication systems at work.  A few google searches later and you’ll find a bunch of results for ‘How to configure Radius with Google Continue reading Not all technical blog posts are created equal.