Microsoft Exchange Online (M365) Maximum Email Message Size Limits (Send and Receive)

Microsoft has announced that Office 365 (Exchange Online) now supports up to 150MB email messages, quite a large increase from the previous limit of 25MB. Within Exchange Online you don’t get the level of control you had on Microsoft Exchange on-premise servers, where you could configure the size limits on Organisation Wide transport configuration, Send/receive connectors, AD site links … Read more

VMware CPU Ready Time

The CPU Ready Time shows how much time the VM is waiting to use the CPU on the VMware Host. Obviously you want this figure to be as low as possible, but typically below 10% is fine. The more you oversubscribe a host, the higher the CPU Ready Time because the VM(s) spend more time … Read more

Using PuTTY to Port Forward to Remote Host

Let’s say you have your workstation with PuTTY installed, and you have accessed a remote machine via SSH. If you wanted to get to a service running on that remote machine you’d either need direct port access from your workstation to the remote machine on that port, or you can tunnel a port (or ports) … Read more

MSExchange OAuth Error – Event ID: 2004

We had an issue with event ID 2004 being logged on our Exchange Servers, grumbling about a missing certificate. Warning Observed The following error is observed: Analysis It seems to indicate that an expected certificate is missing. Running the “get-authconfig” gives this output, and we can see that the PreviousCertificateThumbprint  Confirm Current Certificate Confirm that … Read more

Sudoers NOPASSWD Option Not Working

Although not good security practice, it can be helpful for a user to account to have at least some (or all) sudo ability without the need to re-enter the user’s password to gain sudoers. By adding the user within the file /etc/sudoers (via visudo is recommended for Ubuntu Linux), with the following, you can ensure … Read more

Find Exchange Mailbox Users via homeMDB Attribute

We were completing a migration from Exchange 2016 to Exchange SE, and we found that when attempting to decommission the old Exchange Servers that we could not due to user accounts referring within the homeMDB attribute to a mailbox database on a legacy Exchange 2016 server. In some cases these didn’t actually have a mailbox … Read more