As of version 2.x, Mozilla’s Thunderbird email client forwards email messages as .eml attachments by default. Which is not a particularly good situation, unless you actually enjoy playing ping pong with your mail server.
Make no mistake about it—Mozilla’s Thunderbird is a great email client, and all my friends on PC’s are big fans (clients for the most part tend to be on locked down Windows boxes where Outlook is the IT choice of no-choice). But what’s up with Thunderbird v2.x sending forwarded messages as .eml attachments by default? What the fudge Mozilla?
I got this message today from a client whose email as well as website I host:
Hey mate, is there any way you can see if you can stop the mail server from blocking .eml attachments, as every message I forward is getting bounced back to me?
And here is the error message he was receiving:
This message has been rejected because it has a potentially executable attachment "Message Subject here.eml" This form of attachment has been used by recent viruses or other malware. If you meant to send this file then please package it up as a zip file and resend it.
After briefly considering using Exim Editor to do what the client was requesting for, I don’t know, maybe two seconds, common sense quickly prevailed and, a speedy 0.21s search query of Teh Google later, was revealed to be less than prevailing over at Mozilla. As of version 2.0, Thunderbird is configured to forward messages as attachments—by default!
The solution to this “known issue” is rather simple. Don’t complain to your host or ISP, but rather change Thunderbird’s preferences to forward messages inline:
How to forward messages inline in Thunderbird 2.0
Windows:
Tools > Options > Composition > General tab, switch “As Attachment” to “Inline”.
Mac:
Preferences > Composition > General tab, switch “Forward messages” to “Inline”.
Good tip John.
I’m a big fan of Thunderbird, but am definitely NOT a fan of forwarding messages as .eml attachments. I must have changed the setting when I installed TB, because I have it set to forward messages inline. (phew)
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Ah, reminds me of the good old days working in the design studio of a company with a rigidly locked down IT infrastructure. We “creative types“ had to create a support ticket every time we wished to get an email attachment released—heaven forbid that we might want to send and receive fonts, jpgs, zip files, or html documents in the course of business!
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I have been searching for the answer to this problem for ages, I want emails from my website to be forwarded to my Blackberry. I get the .eml virus message and have switched the forwarding to inline. Does anybody have any other ideas what could be causing this, I am pulling my hair out in frustration.
Thank You
Stuart
I do not think that blocking .eml attachments in outbound e-mail messages from your legitimate clients is a good idea. Sometimes forwarding as an atachment is much better than inline for keeping things intact, e.g. when you want to forward some received HTML spam to the sender’s ISP.
This sort of blocking is precisely the reason I have now been thinking about using another company to host my stuff. My current hosting provider is really good in many aspects, but their SMTP blocks outbound .eml attachments, and they don’t seem to be willing to change it. (Actually, I have found this page of yours while googling whether this is considered a real problem by many people
.) I hate to have to save e-mails as files, change their extension to .msg and then attach them just to circumvent this problem, the only alternative being sending them inline.
I am not writing this to say that Thunderbird’s default behaviour should be “Inline” vs. “As Attachment”, but to emphasize that good providers should not block .eml attachments, at least when directly asked by their clients to stop doing it.
Good points Maksym, and it certainly sounds like you should be able to get your hosting provider to unblock .eml attachments if you require it.
If you are thinking of switching hosting providers (hard sell follows), I can’t recommend WiredTree enough—since switching to them recently I have been astounded by their (excellent) level of customer service and support.
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>I am not writing this to say that Thunderbird’s default behaviour should be “Inline” vs. “As Attachment”
Read “I am not writing this to say that Thunderbird’s default behaviour should be “As Attachment” rather than “Inline””. Sorry, I must have not slept enough
.
John Gillespie:
>Good points Maksym, and it certainly sounds like you should be able to get your hosting provider to unblock .eml attachments if you require it.
Nice to hear you say it. Does that mean that if your client still insists, you will launch your Exim Editor?
To be honest, after reading this page I first thought you are so much “pro-inline” that you might even be offended by my previous comment (although that’s of course not something I would like to cause).
>If you are thinking of switching hosting providers (hard sell follows), I can’t recommend WiredTree enough—since switching to them recently I have been astounded by their (excellent) level of customer service and support.
Thank you for this info. Currently I have been using services from a local company for some reasons, and even if I change my provider I still think about some local guys for the nearest future. However, I will surely keep WiredTree info in mind (and, in a more reliable way, add them to ‘Hosting’ folder in my Favorites
).
@Maksym Yes, my point here indeed was that it seems strange to say the least that Thunderbird’s default behaviour would be to forward a message as an attachment rather than inline.
I would have no problem allowing .eml attachments on my own server, but with the very large caveat that it did not create a security risk, something I would need to do more research into first.
By the way, I fully support your sentiments about trying to stay local with your hosting—I myself have both a local host and an overseas one.
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