Christos Polydorou

Today I'd like to talk about IPFire and a problem I had recently with the network cards. IPFire is my favourite lightweight firewall distribution. It's easy to setup and configure which, in my opinion, makes it perfect for labs and POCs. I have a lab environment set up on my Windows 10 computer with multiple virtual networks and virtual machines. I have setup a virtual network with Active Directory domain controllers acting as DCHP and DNS servers, several test servers and workstations. I have even joined an Ubuntu Server to this Active Directory Domain. All these in a private virtual network... So I had to make internet connection available to those machines. I created a new virtual machine and installed IPFire. I added three virtual network adapters to the virtual machine - one connected to my LAN and the other two connected to two private virtual networks. After a little bit of configuration, my virtual machines could access the internet through the IPFire virtual m

So, you're an Exchange administrator and you have been assigned the task to add multiple recipients to distribution lists. You fire up Powershell, load the Exchange snap-ins and after you have your recipients ready you start adding them to the groups. If a group has managers configured and you're not a manager of the group, the Add-DistributionGroupMember  or  Remove-DistributionGroupMember cmdlets will fail with an OperationRequiresGroupManager exception just like this one: The solution to this is very simple, you have to add the -BypassSecurityGroupManagerCheck  switch to your command. When adding or removing many members I always use this switch cause I do not want to get an error and end up with users being added to some groups just for this reason. Never the less, you can always use Try-Catch to handle the exception or check if the group has managers if you do not want to bypass this check for all groups. You may find more information regarding this exceptio

Kali Linux is an operating system that is - without any doubt - a very useful tool for everyone that is in the IT business. It contains tools to not only check the security of systems but also help examine  and troubleshooting network issues, application issues etc. I've always used Microsoft Windows as my primary operating system and since Hyper-V is available out of the box the last few years, all my virtual machines are running on Hyper-V. Installing Kali Linux 2 on a virtual machine is pretty straight forward, assign the .iso file to the virtual machine's drive, start it and follow the setup wizard. The Hyper-V drivers are part of the operating system, but you have to enable them manually by editing the /etc/initramfs-tools/modules file and adding the following lines: hv_vmbus hv_storvsc hv_blkvsc hv_netvsc After saving the file, execute the update-initramfs –u command for changes to take effect and reboot the virtual machine. To verify that the drivers are l

I had faced a strange Microsoft Exchange issue last week, messages were getting stuck in the submission queue of an Exchange 2010 SP3 Hub Transport server possibly due to an issue on the Transport Rule Agent. While troubleshooting the issue, since there were a lot of messages in the queue, around two thousands, I decided to export them and import them on the second Hub Transport server. In order to export the messages I used the following command: 1 2 3 4 5 6 7 8 9 10 $messages = Get-Message -Queue "EXCHANGESERVER\Submission" ForEach ( $m in $messages ) { $Temp = "C:\Messages\" + $m .InternetMessageID + ".eml" $Temp = $Temp .Replace( "<" , "_" ) $Temp = $Temp .Replace( ">" , "_" ) $Temp = $Temp .Replace( "\\" , "_" ) Export-Message $m .Identity | AssembleMessage -Path $Temp }  I used the Get-Message cmdlet to get all t

There have been many times when a request came in order to forward messages sent a mailbox to another mailbox or mailcontact. This mostly happens when there is an ongoing migration and the user has an account on the other organization that is part of the migration, or they just want their mail to be forwarded to another account in order for them to not have to check multiple mailboxes. But let's cut to the chase! Every mailbox has two properties, ForwardingSMTPAddress and DeliverToMailboxandForward. The ForwardingSMTPAddress is the address where the messages are going to be forwarded. The DeliveToMailboxandForward is the option to leave a copy of the message to the mailbox. So, if you want to just forward the messages sent to user John Smith to john.smith@otherorg.com, you should use: 1 2 Set-Mailbox -Identity "John Smith" ` -ForwardingSMTPAddress "john.smith@otherorg.com.net" 1 2 3 Set-Mailbox -Identity "John Smith" `