Problem when sending mail in Thunderbird

hello there!
this is my first post, and unfortunately it’s problem-related :stuck_out_tongue:

i’m having trouble sending mail in Thunderbird, since i’ve installed comodo firewall 3.
i have tried many configs for the firewall (custom/predefined) and here’s what i get:



please note, that i’m using a thunderbird config that is specially recommended by my ISP.
i know that the problem is firewall-related, because when i manually disable it, the problem’s gone!

sorry for the long post.
thanks beforehand!

ps: sorry if this has been previously answered, but i couldn’t find something as far as i’ve searched.
ps2: IPs/domains are partially/fully masked.

edit: removed the cloned post/thread :slight_smile:

the only thing I can say is that you should apply the email client predefined firewall rule to Thunderbird, but I don’t think this will resolve your issue. I rather think that your error message comes from incorrect settings in Thunderbird (POP & SMTP). Check the ports and the server name. Oh a bad configured antispam filter can also bring such errors.

[b]This thread appears twice, would be a good idea to delete the other one here:[/b]

(lol the post from the other thread has been moved and now we got a duplicated post)

[attachment deleted by admin]

Are you using a proxy mail scanner like Avast!? If not, and you are connecting directly to your email smtp server, add a rule to block and log all at the end of your TB rules so you can see what isn’t getting through to your server with Comodo. What special setup instructions does your ISP give you, other than server IP and use port 25 for smtp?


yeah I’ve had this error message once and i can’t remember whether the issie came from Avast or from my SpamFilter (both proxies). Anyway I solved the problem by reconfiguring something directly related to the mail client, or associated programs, nothing to do with CFP (it’s getting actually mad to see that more and more people put the blame on CFP as soon as something’s wrong on their computer; same phenomenon occurred with the 2.4 version. It’s probably the same in all forums, people try a new software and anything that goes wrong after that becomes the fault of the new software… :THNK :SMLR )

Anyway the only thing CFP can do with an email client is allow it or block it, but I’m afraid it’s not able (yet :SMLR) to send wrong network protocol messages to your mail server.

thank your for your prompt answers!!

let me make clear first, that i do not BLAME comodo firewall for the issue
[blame stands for accuse].

…and it’s been almost a year, since i’ve been using comodo and with no major issues.
so, please don’t get mad at me :slight_smile: - no offense, hard feelings.

it’s true that i use avast. the “special” ISP recommendation has to do with using TLS secure connection, nothing more than that.

once more, thank you for your prompt answers!!!

iomp you misunderstood me, I didn’t get mad at you all. I just made some general comment on how many users react to issues that occur on their computers after they’ve installed new software, issues they would have had anyway. Nothing personal.

Now another thing: how do you get Avast work with a secure connection (SSL or TLS) on your mail client? I know this is possible cause I do it myself. You might have made a mistake with the software you use to make it possible.

And did you check the ports allowed by CFP on Thunderbird, Avast, and any third party software to allow SSL connections? if all required ports are allowed on the applications, CFP can’t block them. Again, CFP cannot “corrupt” a connection.

Did your setup instructions for TLS tell you to use port 25 or some other port? Secure email often uses different ports (outbound gmail uses 465 and 587, for example). And are you using stunnel? If so, you need to add your proxy/loopback ports under Comodo. And tell us what proxy ports you are using with stunnel. Comodo restricts the ports used for email, and Avast! doesn’t directly send secure email. If you are using Avast!, look under On access protection control/internet mail/customize/smtp. Temporarily uncheck “scan outbound mail”. Under TB, you need to allow both the loopbacks and the proper ports. For now, add the following rules under thunderbird.exe allow&log/tcp/out/any/any/any/any and at the end of the rules “block&log/IP/in&out/any/any/any”. My rules are attached, but still need to define the ports used with you and refine the rules for your setup. Also a gmail smtp setup for TB. If you are scanning with avast, the server would be localhost and the port would be the proxy port used in stunnel (11025 or such), and use secure connection would be “no”. And you need to tell CFP about all this or use the simplified rules mentioned previously. :wink:

[attachment deleted by admin]

Not sure if this will help or not, but I set up my son’s Sympatico DSL connection and it took a half hour or so to get TB to send mail. Sympatico uses a Hotmail server for mail and they said to use SSL and port 995 (I think that was the port number), but I had to use “TLS if available” and the mail sent fine. BTW he uses Avast as well.