CE SMTP without SSL

[ogk.nz]

I have a remote system that I am trying to develop that is based on a windows CE 5.0 device. This system is supposed to be able to send emails about its current status alarms etc to listed email addresses and the like. Using touch panel module and TCP I have managed to make the device Telnet into an SMTP server however once there it is unable to do anything since all of the smtp servers that I am aware of require both SSL and Authentication.

The point is this, does anyone know of any SSL unsecured but Authorised STMPs that are reasonably easily publically accessible?(i.e. yahoo, gmail)

Secondary option is finding a way to enable SSL on the device, I'm not sure if this is possible using LabVIEW, there have been plenty of mentions of STunnel throughout the forums and the internet but my understanding is that it simple acts as a forwarder through an SSL enabled computer. As this device is meant to be a standalone this in not a viable option.

Anything to help get this project moving again would be greatly appreciated.

[MegaWatts]

Hey,

First of all, what version of LabVIEW are you planning on running on the device? I was able to find an KnowledgeBase Article that describes how to use a secure SMTP server with SSL, I'm not sure if you have seen this yet, or if this will be helpful.

http://digital.ni.com/public.nsf/allkb/484272384C2960AA8625749E006512EE

[ogk.nz]

I am using LabVIEW 2012 with touch panel module as this is the latest version of LabVIEW to actually support interaction with Windows CE Devices. The problem with that article is that when I attempt to use it with the CE device it draws up an error about missing system.dll, which I am assuming is a .Net dll that I don't believe works with Windows CE. Even when running it on the development PC it runs fine with SSL disabled, but when you try to enable SSL it throws System.Net.Mail.SmtpException.

[rolfk]

The .NET Compact framework, which is what Windows CE uses, doesn't support System.Net.Mail or System.Web.Mail. You can probably use an extension such as http://www.opennetcf.com/library/sdf/html/7e16eccb-dc9e-4559-c79c-cfaad631ac15.htm instead.

[ogk.nz]

That looks like it could work and makes a sort of sense but given I'm not even a CLAD yet, can you give me some pointers on how to start implementing the NETCF. stuff in vis? A link to an example or tutorial of any kind would be greatly appreciated.

[rolfk]

I'm very sorry but I have no CE device available to even try it out. Am also not sure if that library supports SSL, but Windwos CE comes with SSL support so if one gets at least the standard version of their component it would also include the source code and could therefore be fairly easily adapted to support SSL too. In any case you most likely need to get/buy such a component and install it in your CE device and then interface to it from LabVIEW.

[ogk.nz]

I know that the device is capable of communicating over SSL as it has a web browser available which can be used to navigate to HTTPS:// websites. However when using TCP communication to try and communicate with an smtp server the connection is rejected due to SSL not being enabled. From what I have gathered it is impossible to apply SSL to a TCP connection so some other method of communication is needed in order to connect properly to the smtp server.

Trying to dig the source code out of the web browser is going to prove nigh impossible, so unless I can find a good guide to using .NetCF, possibly with LabVIEW I think this project may be stalled, or possibly the next best option will be to have the CE device operate as a network client and connect directly to a LabVIEW server. The information doesn't really need to be secure as it will simply be raw measurement data so the LabVIEW client server communications should be fine.

[rolfk]

Well you have two options to use for safe SMTP. One is using an SSL connection and the other is using STARTLS. Both eventually use SSL anyways but while SSL starts with an SSL connection right away, STARTLS uses first a normal connection and then switches over after negotiating an SSL connection.

And it is of course possible to use SSL with TCP. How exactly this is done in .Net I wouldn't know however, I only have some experience in Java, but .Net works in many ways very similar to Java. In Java the use  of SSL is somewhat complicated and feels in respect to other programming languages quite backwards but does work for sure.

And yes I said that Windows CE comes with SSL support, but it indeed only uses it in the HTTP library and not in any others. It still would be possible to use that for an SMTP communication too, but it seems there are very few who did that and from those who did even less have considered to release it to the public for free use.