Microsoft Exchange and Active Directory Blog
I wish all friends, readers and supporters a merry and peaceful Christmas, take care of yourselves and stay healthy. I wish all admins who are looking after the well-being of the systems during or between the holidays every success. Take a few days off as soon as possible and treat yourselves and your loved ones to something nice. ... Read more
Attacks on outdated Exchange servers are currently underway again. Specifically, the ProxyNotShell vulnerability, which became known in October of this year, is being exploited again. The new attack method has been christened OWASSRF. The IIS rewrite rules published by Microsoft are bypassed in this new attack method. The only thing that helps at the moment is to install the available security updates from November: On the ... Read more
In this article I try to explain why you should avoid some special Backup MX configurations. The configuration of a Backup MX at the provider or hoster is outdated and should no longer be used. Backup MX at the provider I have often come across the configuration with a Backup MX entry for the provider. The MX entries ... Read more
Many admins are familiar with the problem that size limits have been configured for mailboxes and every now and then there are messages about full mailboxes from users. As an admin, you really only have two options here: either you increase the mailbox size for the user, or you tell the user to clean up and delete old mails. The first ... Read more
A size limit for emails can be configured at various points on an Exchange server. The limits can be configured very granularly, for example at mailbox or protocol level. This article lists the options available. This article also applies to Exchange 2016. TransportConfig: Global size limit The global limits for emails are configured in TransportConfig. Read more
On Tuesday, Microsoft released new security updates for Exchange Server 2013, 2016 and 2019. The update closes the ProxyNotShell vulnerability (CVE-2022-41040 and CVE-2022-41082), which was known and actively exploited in September. Click here to download the security updates: Microsoft recommends installing the update as soon as possible. Click here for the article on the Exchange ... Read more
Two Outlook Autodiscover settings, which are active in the default setting, often cause problems when setting up Outlook accounts. In the default setting, Outlook always tries to retrieve Autodiscover settings from Microsoft 365, which often leads to problems with on-prem Exchange servers. Outlook also tries to retrieve the Autodiscover settings from the root domain ... Read more
AutoMapping is a very practical feature in Exchange Server, but unfortunately it is somewhat limited: AutoMapping only automatically connects a mailbox in Outlook if the user has full access to the mailbox. As soon as granular permissions are configured at mailbox level, AutoMapping no longer takes effect. In this case, the user must manually reconnect the mailbox with the granular rights. ... Read more
Unfortunately, Exchange 2019 only offers a few settings for resource mailboxes (room and device mailboxes) in the Exchange Administrative Center. Many settings for booking permissions or calendar settings can only be managed via the Exchange Management Shell. Create resource mailboxes with the Exchange Management Shell With small PowerShell scripts, resource mailboxes can be created quickly and always according to the same scheme. Here ... Read more
I have just uploaded the new version 3.11 of the Exchange Reporter. The new version contains the module "ExchangeMitigations", which shows the status of the Exchange Emergency Mitigation Service and the applied rules. Here is an example report of the new module: Various bugs have also been fixed, the module "Healthchecker", which executes the Exchange Health Checker Script and displays in ... Read more
