rmd for thunderbird too

That was easy.

I was recently asked about the possibility of adapting the Remember Mismatched Domains extension to support Thunderbird. Well, it turned out to be a snap. All I had to do was add Thunderbird as a target application in the extension’s install manifest. How cool is that?

What is Remember Mismatched Domains?
The Remember Mismatched Domains extension for Firefox and Thunderbird adds a “Don’t warn me again about this certificate for this domain’ checkbox to the Domain Mismatch warning window. When selected the domain name and security certificate domain pair is stored in a Firefox / Thunderbird preference and the security error dialogue will be bypassed on subsequent visits.

(I explained why I wrote the extension in the original announcement).

How do I install the extension?
If you want to install the extension in Thunderbird, you have to follow these steps:
1. In your default browser, right-click on the download link. Choose the “Save link to disk…” option and download the XPI install file into a directory of your choosing.
2. Open Mozilla Thunderbird and open the ‘Extensions’ dialog by going to the ‘Tools’ -> ‘Extensions’ menu.
3. On the Extension dialog, there’s a button named ‘Install’ in the lower left corner. Click on it and browse to the directory where you saved the remember-mismatch.xpi.
4. Choose the file you downloaded earlier on and click ‘OK’.

Firefox users left click on the link.

It’s a beta and could use some testing in different environments. The comments section would be a good place to let me know of any issues.

Update (Oct. 08, 2005): version 0.6 supports both Thundebird 1.5 Beta 2 and Firefox Beta 2.

Update (Oct. 25, 2005): version 0.7 fixes an issue where certificates with names containing space characters were not being properly “remembered”. My apologies to Emmanuel’s dad for the delay ;-)

38 Responses

  1. yomguy says:

    October 3, 2005 at 5:39 am

    Thunderbird’s extension works very well !
    Thanks !

  2. Alexander Sick says:

    October 6, 2005 at 6:29 pm

    Thanks a lot for implementing the version for Thunderbird so quickly. Works very well and saves me many mouseclicks :-)

  3. Revolage says:

    October 6, 2005 at 6:39 pm

    Great idea! However, could it be updated to work for Thunderbird 1.5 Beta 1?

  4. andrew says:

    October 6, 2005 at 6:59 pm

    Thanks for the feedback gents.

    I’ll try to get a chance to look at the TB beta…

  5. Emmanuel Lemor says:

    October 22, 2005 at 12:22 am

    Great extension but it’s not working :(

    Thunderbird v1.5b2, and Visnetic Mailserver using SSL:
    Certicate data shows up in the extension option area but every time you connect even if you check the box it re-enters the same info into the extension and the next time it pops up again with the same checkbox [which is unchecked], my guess is because the extension is not exactly parsing the data correctly…

    When you connect the IP of the mail server comes up under the Website Domain column and the Cert. Domain comes up BUT this email server has a 2 word domain name separated with a space [I know, i know not a very legit
    domain name but often found in softwares - the name of the product is often used by softwares instead of paid for SSL domain name].

    If you want I can give you a test account on this server for testing purposes, please contact me via email if you need additional information.

    Thanks :)

    Sincerely, Emmanuel

  6. Emmanuel Lemor says:

    October 22, 2005 at 12:25 am

    It doesn’t look like my email shows up on this interface, it is: exlemor@gmail.com

  7. Stephan says:

    October 22, 2005 at 5:25 am

    I have a problem. One of my SSL-names is separated with spaces. So the extension does not work. B/c the extension saves each separated with a space.

  8. andrew says:

    October 22, 2005 at 11:57 am

    Emmanuel, Stefan,

    Thanks for the reports. You’re absolutely correct, the RMD extenstion uses a space character to seperate stored domain name pairs. Spaces in the cert common name will cause the issue you’re experiencing.

    As way of explanation, I was concerned about doing it this way so checked with VeriSign’s enrollment procedures. They require the common name be host + domain name such as “www.company.com” or “company.com”. I wrongly assumed this was as per the SSL specification.

    Anyway, I’ll need to fix this. Stay tuned…

  9. andrew says:

    October 22, 2005 at 12:17 pm

    It doesn’t look like my email shows up on this interface…

    My Wordpress install is setup to never display email addresses entered in the E-mail field publicly. This is to help prevent address harvesting by spam bots. If this a concern for you say the word and I’ll edit the address out of the body of your post above.

  10. Justin Force says:

    October 25, 2005 at 3:27 am

    Thanks ever so much for creating this extension. That dialog was driving me crazy. Every single time Thunderbird checked my email…

  11. Emmanuel Lemor says:

    October 25, 2005 at 4:02 am

    Hi Andrew, my bad, I use Joomla a lot and it has smart email masking technology and I assumed that WordPress did too… [that's what you get for assuming]…

    Not trying to be a bug but I was wondering how difficult that space thing would be to fix? :) :) [meaning how much time...] You’re going to laugh but actually it’s for my dad, and he is not as patient as I am, I told him this ingenious programmer who already made this add-on for Thunderbird is working on it… :p


    Emmanuel Lemor.

  12. Oliver Fuerst says:

    October 25, 2005 at 7:36 am


    I took a look at your Thunderbird extension and stumbled across the same problem as other users pointed out (separation by space). I took the liberty to unpack remember-mismatch.jar in the extensions folder and replacing the split char ” ” by “#” in options.js and remember_mismatch_overlay.js. Now it works smooth for me, as one of my mail domains has a space in the domain name. This is a kind of quick fix, better would be to escape and unescape the saved pairs.

    Thanks for this great extension. Helped me staying sane and not clicking OK every 10 consecutive minutes.


  13. Oliver Fuerst says:

    October 25, 2005 at 7:45 am

    P.S. You can download the patched remember-mismatch.jar here
    admin link removed (with Oliver’s permission)

    For the quick install:

    1. Shutdown Thunderbird
    2. Search for “remember-mismatch.jar” in your user’s profile extension dir
    3. Replace it with admin link removed (with Oliver’s permission)

    You will need to check the “Remember …” checkbox once again, and if you told the RMD extension to remember anything before, you can delete the now the first bogus entry (old separation by space) from the RMD option dialog.

    admin: RMD extension now supports spaces. The patch is no longer necessary. Thanks again Oliver!

  14. andrew says:

    October 25, 2005 at 7:45 pm

    Okay version 0.7 is up now and it should fix the space issue. Sorry for the delay I’d made the changes and never found time to test adequately. I was a little concerned about it messing up any existing remembered domain pairs (valid ones of course). I think all should be fine.

    Oliver, your second post got caught in my spam filter (not sure what set it off) hence the delay in it becoming visible. Your efforts are appreciated big time. Thanks for making it available!

  15. Emmanuel Lemor says:

    October 25, 2005 at 8:06 pm

    My dad thanks you very much.. :p and me too for he is not bugging me now :p hahah


    Emmanuel Lemor

  16. andrew says:

    October 25, 2005 at 8:09 pm

    My dad thanks you very much.. :p and me too for he is not bugging me now :p

    Cheers. Holler if anything seems wonky.

  17. Albert says:

    November 16, 2005 at 11:44 am

    This extension is great, it helps me using my Thunderbird a lot :)

    Could you possibly do the same for the “Certificate out of date” warning?

  18. Greg says:

    November 18, 2005 at 3:54 pm

    Oh my, this is so brilliant. Thank you so much for doing this. I can finally use my hostrocket imap mail in secure server mode without that persistent warning. This makes me very happy. Thanks thanks thanks.

  19. Michael Moore says:

    February 6, 2006 at 12:47 pm

    I added this extension to the new DreamHost KnowledgeBase Wiki so more people can use it from DH. I’ve been looking for something like this for a while. Thanks!!

  20. Michael Moore says:

    February 6, 2006 at 12:48 pm

    Oh, the DreamHost page is here.

  21. Matthew McCabe says:

    April 19, 2006 at 1:01 am

    Thanks for the extension! You have made my life migrating to Thunderbird much easier!

  22. Mark Evenson says:

    May 18, 2006 at 8:51 am

    Thanks for writing this extension. I am using SSH port forwarding to get to my email (long story involving corporate firewalls and such), and the certificate mismatch message every five minutes was driving me crazy!

  23. Remembering Mismatched Domains In Thunderbird… at EdgeCloud.__init__() says:

    May 25, 2006 at 12:20 am

    [...] You gotta love those days when find a tool that helps you save time on a repetitious, but important task. Enter the Remember Mismatched Domains extension for Firefox/Thunderbird. Wow! Drop dead simple extension that allows you to tell the app not to keep bothering you about a certificate (SSL) that doesn’t match the domain you are talking to. Now certainly the check in and of itself is good. But when you are hosting your email through Dreamhost which has SSL but doesn’t yet allow you to have specific certs attached to your mail domain…that’s bad (and time consuming!). Cheers to the developer on this one… [...]

  24. Andy says:

    June 15, 2006 at 10:36 pm

    Thanks. Solved this problem wonderfully.

  25. Aaron says:

    July 24, 2006 at 8:19 am

    Thanks, Andrew, this extension saved my sanity this morning.

  26. Orde says:

    October 2, 2006 at 5:29 am

    Thanks, saves servers timing out when opening thunderbird and going for a coffee.

  27. Link With Reality Web Log » links for 2006-11-03 says:

    November 6, 2006 at 7:56 pm

    [...] rmd for thunderbird too Do you use SSL when checking email, but get annoyed at having to hit OK for the mismatched domain? This extension will fix the problem. (tags: software) Links :: John :: [...]

  28. BRYAN’S BLOG » Blog Archive » Domain name mismatches in SSL certificates says:

    November 28, 2006 at 4:55 pm

    [...] For Thunderbird (win or mac), see this posting. [...]

  29. Greg P says:

    December 30, 2006 at 1:44 pm

    Great extension — makes using Thunderbird much easier! Thanks.

  30. pht3k says:

    February 14, 2007 at 3:42 pm

    thx a lot; very appreciated!!

  31. Dale says:

    February 15, 2007 at 5:20 pm

    Dude, this extension is totally awesome.

  32. Dan says:

    February 28, 2007 at 7:33 pm

    Great extension. I was getting multiple email accounts through Thunderbird and the cert warning was a real pain. It works great, thanks a lot!

  33. Somewhere out there! » Blog Archive » Remeber Mismatched Domains for Thunderbird (and Firefox) says:

    March 7, 2007 at 8:56 pm

    [...] Useful extension, especially for those self-sign SSL certs: rmd for thunderbird too. [...]

  34. Michael Wallis says:

    April 27, 2007 at 2:12 pm

    The current plugin does not load in either Firefox 2.0 or Thunderbird 2.0. Will there be an update any time soon??

  35. andrew says:

    April 27, 2007 at 6:31 pm

    Hi Michael,

    You can grab the latest version of RMD (which should install in both FF2 and TB2) from here:

  36. Jubilee says:

    July 3, 2008 at 9:07 pm

    Thank you so very much for this add-on………I’d been doing many many many mouse clicks a day for months because of the domain mismatch. I finally began to get fed up today, searched for a answer to this madness. ^_^ And there you were. Take Care.

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