Microsoft

Tech Tip: Display Win2K services during startup/Configure reverse lookup for SMTP

Learn how to display Win2K services during startup and configure reverse lookup for SMTP.

Windows 2000 Professional: Display services during startup

One of the many benefits of Windows' Safe Mode is that it displays services as they boot. This can help you identify services that could be causing the system to hang. However, booting in Safe Mode also disables a variety of services, some of which you might need to troubleshoot the problem at hand.

Whether you're troubleshooting a problem or you just want to see what's going on when Windows boots normally, you can easily view services as they start. Just add the /SOS switch to the line in the Boot.ini file that starts with Windows 2000.

Boot.ini doesn't appear in Windows Explorer by default. To view it, open the root folder of the boot drive, and go to Tools | Folder Options. On the View tab, deselect the Hide Protected Operating System Files option.

Double-click Boot.ini to open it in Notepad. In the [operating systems] section of the file, locate the line that starts with Windows 2000. Except on a dual-boot system, this section typically contains only one line.

Add a space and the /SOS switch at the end of the line. Or copy the line, insert the copy below the original, and add the /SOS switch to the copied line. Change the description within the quotes to indicate the purpose of the entry, such as "Windows 2000 Professional Verbose Boot."

Save the Boot.ini file, and reboot the system. If you edited the default boot line, you should now see a list of services appear as the system boots. If you added a line with the /SOS switch, choose that entry from the Boot menu to boot the system with services displayed during startup.

Windows 2000 Server: Configure reverse lookup for SMTP

You can configure many e-mail servers to perform a reverse DNS lookup for a host record in the sending server's domain that matches the IP address of the sending server. Validating servers in this way can reduce spamming because the system rejects messages from nonvalidated servers.

Windows 2000's SMTP service, which you manage through the IIS console, offers several advanced delivery options. To view these options, click Advanced on the Delivery tab of the virtual server's properties.

One of these advanced options is Perform Reverse DNS Lookup For Incoming Messages. But this option doesn't do what you might think it does.

Windows 2000's SMTP service doesn't accept or reject connections based on the success or failure of a reverse lookup. Instead, when you enable the reverse lookup option, the SMTP service performs a reverse lookup on the sending server.

If the existence of a PTR record in the target reverse lookup zone verifies the server, the service makes no changes to the message's RECEIVED header. If the reverse lookup fails, the word "unverified" appears after the IP address in the header.

While this reverse DNS option can be useful in identifying messages that were sent from servers with (or without) valid PTR records, it does nothing to curb spam. In addition, enabling reverse lookup will certainly increase network traffic and decrease server performance, particularly if your server receives a large number of messages.

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