Turn off your SMTP, Telnet and HTTP banners
This tip was submitted to the SearchWin2000.com tip exchange by member Mark Mills. Please let
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When you Telnet to your mail server (port 25) from a command line, (c:telnet
25), it displays what SMTP server you are running. The same goes for Telnet(23) and
HTTP(80) ports. This leads to an "OS Fingerprint" so hackers can decide on what
vulnerabilities you have to attack. What can you do to block this in Windows 2000? Use the Meta
Editor provided free of charge from Microsoft. For more information see <A
and download the editor at <A
<P>This editor works for the SMTP service bundled with Windows 2000 server and for Exchange.
For Windows 2003 people, change the default connection response that you receive after you connect
to the SMTP port in Exchange 2003. For more information see: <A
<P>For Telnet banners: Change the Telnet Server Banner and Run Programs for All Users. See
Microsoft Knowledge Base <A
for more information. <P>For HTTP banners -- sorry I couldn't find a free
way to do this – try <A
<P>This way you won't be telling the hackers what type of Microsoft OS/application your
running. If you've never heard about OS fingerprinting and what can become of it, read this
abstract at: <A
This was first published in June 2004
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