On Sun, Oct 24, 2010 at 11:22:24AM +0200, martijn.list wrote: > > Just use opportunistic TLS on both ends and go. > > It depends on the requirements whether TLS is good enough. It's not > always possible to be 100% certain that the complete route is TLS > protected. All intermediate servers should protect the message with TLS > and this is something the sending server cannot enforce. For example if > you are using fallback SMTP servers hosted by some external company in > case of problems how can you be 100% certain that the email is TLS > protected?
The "secure" and "fingerprint" TLS security levels address this issue. > If your requirements are such that you must be 100% certain that your > email is protected all the way, you should protect the message, not just > the channel. No, protecting the channel is quite sufficient, and by the far the simplest approach, if the goal (as stated) is secure delivery between two sites. -- Viktor.