We found that the following steps worked, and we can predictably edit the settings in the IIS 6.0 Manager without errors (and without crashing when applying settings):
- Stop the
SMTPSVC service (Display Name: "Simple Mail Transfer Protocol (SMTP)")
- Stop the
IISADMIN service (Display name: "IIS Admin Service")
- Edit C:\Windows\System32\inetsrv\MetaBase.xml
- Find
<IIsSmtpServer Location ="/LM/SmtpSvc/1"
- Add
RelayIpList="" as an attribute. (Settings are alphabetical.)
- Save the MetaBase file.
- Start the
IISAdmin service.
- Start the
SMTPSVC service.
You can now open the Internet Information Services (IIS) 6.0 Manager (InetMgr6.exe) and work like normal. The setting above relates to the Access Tab > Relay Restrictions section, but doesn't set anything in it (i.e. It sets "all except the below list" with a blank list).
After setting this value, you can change it to what you need it to be. (i.e. The value doesn't need to be 'null' for the fix to work, just so long as the variable key is present in the file).
The steps above have been tested on a few new installs of Windows Server 2022, and have worked for us every time. If you have done an upgrade there are some other things to consider. (It seems like the SMTP service is not installed after upgrade, so you will require a backup of the settings that can be applied post reinstalling the service. But that is discussed in other topics.)
PS: Remember to set the SMTPSVC service to start "Automatically". By default it's set to "Manual".