IIS6 SMTP and TLS on outbound connections

iis-6smtptls

In the options for setting up the SMTP server hosted in IIS, there exists an option to enable TLS on outbound connections which I want. However I also want it to be able to fallback to clear text in the event that the mail server it is talking to is not TLS enabled.

Will IIS6's SMTP server do that? Or will I need to setup two SMTP servers, one TLS enabled for outbound connections, and one not?

Best Answer

There is no way to create an opportunistic SMTP server in IIS. You'll need to create two virtual SMTP servers (one with TLS required, and one without) and route mail accordingly.

http://www.phreek.org/index.php/prkblog/comments/enable_tls_on_your_iis_60_smtp_virtual_server

Related Solutions

Setting up SMTP in IIS6

This guide has all you ever needed (or wanted) to know about SMTP in IIS 6. Expand the selections on the left and look at the SMTP Security subject in particular.

http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/e4cf06f5-9a36-474b-ba78-3f287a2b88f2.mspx?mfr=true

Security – How to inspect remote SMTP server’s TLS certificate

You can use OpenSSL. If you have to check the certificate with STARTTLS, then just do

openssl s_client -connect mail.example.com:25 -starttls smtp

or for a standard secure smtp port:

openssl s_client -connect mail.example.com:465

Best Answer

Related Solutions

Setting up SMTP in IIS6

Security – How to inspect remote SMTP server’s TLS certificate

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