DKIM (DomainKeys Identified Mail) is a way to help validate the authenticity of the emails you send. DKIM adds a signature to your email by using a private key and a public key. Your public key is your DKIM DNS record and only your email server knows your private key. When you have DKIM setup…
Back in 2015, Microsoft enabled all Microsoft 365 (aka Office 365) Exchange Online tenants the ability to change their message sizes to a maximum size of 150 MB. Originally the default size was 25 MB and previously Microsoft increased that to 35 MB, your tenant will likely be set to one of those values. The…
For whatever reason the default fresh setup of Microsoft 365 has no audit logging turned on. Audit logging is very useful for IT troubleshooting and auditors love logs. Microsoft says that it is enabled by default for Microsoft 365 and Office 365 enterprise organizations. I suspect that means only if you have E1 or higher.…
Right out of the box the initial configuration of Microsoft 365 (aka Office 365) isn’t bad, but there’s a lot more you can do to harden it and to make it fully yours. By default all Microsoft 365 tenants are in a state that is called dehydrated. Microsoft places all the tenants in this state…
My firewall recently blocked Microsoft Azure AD Connect which caused issues with syncing to 365. Turns out the issue was that my IPS (Intrusion Prevention System) flagged it as being “suspected RST injection”. Normally when something like this happens it’s typically the IPS being overly sensitive and I usually can whitelist the specific detection however…
Update The process detailed below has been deprecated by Microsoft. An updated version of this process is detailed in my post called Swap Microsoft 365 Licenses with Microsoft Graph. I needed to remove some expired Office 365 licences that were expired to the point where I couldn’t do it via the admin interface so I…
