Exchange Server 2010 & the “x-originating-ip” header

Today I ran into a very strange problem. I’m running an Exchange Server 2010 SP1 and an Exchange Server 2007. The Exchange Server 2007 is inside our company’s network, protected by a SecurePoint Firewall. The SecurePoint Firewall is having Greylisting enabled, so sendmail is filtering all the mails flowing to the E2K7. Whenever I sent an email from the 2010 SP1 (outside the firewall) to the Exchange Server 2007 (behind ┬áthe firewall), it was returned with the error message

554 5.7.1 Command rejected
after the SMTP "DATA" command was sent.

Continue reading Exchange Server 2010 & the “x-originating-ip” header

Testing Responsive Designs with Opera Mobile Emulator

When it comes to testing responsive webdesigns, testing with real mobile devices can hardly be replaced with anything. However, testing alpha versions of your web project can be done easier. I’ve read an article about Opera Mobile Emulator today on Smashing Magazine, and it seems to be quite useful. It’s Opera Mobile available for regular computers, allowing for checking how a website looks and behaves at different resolutions and pixel densities. Continue reading Testing Responsive Designs with Opera Mobile Emulator

Ubuntu VM not starting on XenServer after kernel upgrade

A few weeks ago I explained how to get Ubuntu 12.04 LTS running on Citrix XenServer 5.6.

Today, after upgrading the VM’s kernel from 3.2.0-24-virtual to 3.2.0-25-virtual, the VM didn’t start anymore. XenCenter showed the following error message: Continue reading Ubuntu VM not starting on XenServer after kernel upgrade

KeeBook: An open source web application for managing passwords

Over the last months, I’ve been working on KeeBook – an open source, web-based application for managing login data. Before, I used to employ KeePass which did its job quite well. However, I always wished this was web-based so I could access my usernames, passwords, notes, etc. on the go. So I found a web-based alternative to KeePass was a good idea. Continue reading KeeBook: An open source web application for managing passwords

Ubuntu 12.04 on Citrix XenServer 5.6

After upgrading my virtualized Ubuntu 11.10 installation to Ubuntu 12.04 Precise Pangolin, I’ve had strange problems on booting up the virtual machine: Sometimes it booted up smoothly, sometimes it hung, sometimes it reported a read-only filesystem due to errors (which actually could not be found using fsck). After some investigation, I decided to re-install the system. Continue reading Ubuntu 12.04 on Citrix XenServer 5.6

Options for embedding content into foreign websites (widgets)

Suppose you offer content that can be integrated into others websites, especially websites not run by yourself. Think of widgets, video players, advertisements, calculators, and so on for example. There are various options of doing this. I want to show you these options and their pros and cons from my point of view. The arguments may differ depending on your concrete situation. Continue reading Options for embedding content into foreign websites (widgets)