Destination Host Unreachable

Back to basics. How do you determine the "free" IP address, and how do you test it?

Nagios and Service Monitoring proofs of concept

When it comes to service management, either for internal use or as a Service Provider, you really should not underestimate the impact of service monitoring.

Netiquette: my experience with some contacts on LinkedIn

Gathering contacts on LinkedIn is usually a positive experience, always a good way to meet new people and share information and knowledge. Yet sometimes it can feel a pain. Here comes a short point of view.

Watchguard SMTP Proxy Rejecting e-mails with error 500 Line Too Long

Some senders get a 500 error message after being dropped by Watchguard SMTP Incoming Proxy rule with the following error: SMTP error from remote mail server after end of data: host xxxx [1.2.3.4]: 500 Line too long

Firewall aid - getting more than just a security box from your XTM

How some simple configuration best practice (developed in time) made my Watchguard firewall not only defend networks, but also helped to prevent security problems.

Coding ache: underlying systems upgrade...

A thought about a tricky process: the patch/upgrade process. It always is a pain when it comes to it, but face it: you need to patch a system to gain new features or bug fixes. Yet, it still scares the hell out lots of people.

Kerio Workspace Starter

I have been working a little with Kerio Workspace Starter edition... though... a little opinion about it.

Watchguard XTM 11.6.1 VPN Authentication Failure

I have found XTM 11.6.1 (and some earlier versions) of XTM OS sometimes loses authentication mechanism on VPN SSL configuration.

Watchguard HTTPS-DPI and Dropbox

Standard HTTPS DPI policy on a Watchguard XTM device will not allow Dropbox to connect, resulting in a "Unable to establish a secure connection" error. Here comes a quick guide to allow Dropbox through your XTM Device.

New PHP Class project for Microsoft ActiveSync

Started a new proof for the Alice Framework to integrate Microsoft ActiveSync into my application.

About Me

Sebastian En3pY Zdrojewski

I have been working as an IT professional since late 1990s. I had the chance to build a horizontal skillset that allowed me to approach almost any IT related project. Since 2005 my role has mainly been as CTO in different companies, spacing between small ISPs and System Integrators. My main area of interest has been IT Architecture, Network and Data Security and protection.

Since 2017 I am workig on a new platform for Intellectual Property and Copyright assets protection and management and founded a company called Rights Chain. The Company's vision is to create a comprehensive platform for effective management and protection of Intellectual Property and digital assets, as well as facing ethical issues like Reputation and Privacy.

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