Good day. I need to be able to use Thunderbird to connect to a mail server (IMAP/SMTP) that has an obsolete TLS version (1.1) and I don't want to low the TLS minimum version on my computers. For this need I would like to use stunnel between Thunderbid clients and the mail server. I tried to use tutorial [1] plus "sslVersion = all" option, but I think the guide is quite incomplete. Do you have any other guide/tutoral that is more complete? Thank you
[1]: https://petermolnar.com/secure-smtp-and-imap-sessions-with-stunnel/
The tutorial you're using is too old. You did not specify the OS ans stunnel version you're using, but what you want to achieve can bedone. The flow we need is this:
You need to specify 2 stunnel sections in your config; one to connect your new clients with TLS 1.2 or higher and other to connect to your mail server with TLS 1.1. Something like this: client tls>=1.2)--> stunnel-server_mode --> Stunnel-client_mode --> mail-server (tls1.1)
For example, assuming the following:a) Your stunnel proxy runs on the same machine as your IMAPS/SMTP server with IP address x.y.z.wb) your IMAPS service is listening on port 143 for IMAPS tls1.1 and the service listens in IP 127.0.0.1 (loopback) c) you want to test TLS 1.2 or later by connecting to port 993 for IMAPSd) We use auxiliary port 1143 on loopback interface (any free port will do).
then, the config should include something like:
sslVersion = alloptions = NO_SSLv2 options = NO_SSLv3
[imaps-external]accept=x.y.z.w:993connect=127.0.0.1:1143 client=nooptions = NO_SSLv2 options = NO_SSLv3 options = NO_TLSv1 options = NO_TLSv1.1
[imaps-backend]accept=127.0.0.1:1143connect=127.0.0.1:143client=yes
Hope this is helpful.
Regards,Jose
On Monday, January 31, 2022, 09:16:55 AM GMT-5, Caterpillar caterpillar86@gmail.com wrote:
Good day. I need to be able to use Thunderbird to connect to a mail server (IMAP/SMTP) that has an obsolete TLS version (1.1) and I don't want to low the TLS minimum version on my computers. For this need I would like to use stunnel between Thunderbid clients and the mail server. I tried to use tutorial [1] plus "sslVersion = all" option, but I think the guide is quite incomplete. Do you have any other guide/tutoral that is more complete? Thank you
[1]: https://petermolnar.com/secure-smtp-and-imap-sessions-with-stunnel/ _______________________________________________ stunnel-users mailing list -- stunnel-users@stunnel.org To unsubscribe send an email to stunnel-users-leave@stunnel.org
Thank you Jose, but a few days ago I solved with the following conf file
[thunderbird<->stunnel] cert = /etc/stunnel/stunnel.pem sslVersion = TLSv1.3 accept = 50050 connect = 127.0.0.1:50001
[stunnel<->xxxxxx] client=yes CApath = /etc/ssl/certs sslVersion = TLSv1 accept= 127.0.0.1:50001 connect=xxxxxxx:993
and in |/etc/crypto-policies/policies/modules/TLS10.pmod| inserted ===== protocol = TLS1.1+ TLS1.0+ min_tls_version = TLS1.0 hash = SHA1+ =====
then run command | # update-crypto-policies --set DEFAULT:TLS10| ||
OK, I see you’re using stunnel only on your client and it looks you’re connecting using TLS 1.0 which is deprecated.
My proposed solution runs stunnel on your server and aims to implement a front end proxy to the imap/smtp product. This can give you the support for new TLS versions and no need to run stunnel on your clients.
regards Jose
On 9/02/2022, at 12:00 PM, Caterpillar caterpillar86@gmail.com wrote:
Thank you Jose, but a few days ago I solved with the following conf file
[thunderbird<->stunnel] cert = /etc/stunnel/stunnel.pem sslVersion = TLSv1.3 accept = 50050 connect = 127.0.0.1:50001
[stunnel<->xxxxxx] client=yes CApath = /etc/ssl/certs sslVersion = TLSv1 accept= 127.0.0.1:50001 connect=xxxxxxx:993
and in /etc/crypto-policies/policies/modules/TLS10.pmod inserted ===== protocol = TLS1.1+ TLS1.0+ min_tls_version = TLS1.0 hash = SHA1+ =====
then run command
# update-crypto-policies --set DEFAULT:TLS10
Il 10/02/22 01:56, Josealf.rm ha scritto:
OK, I see you’re using stunnel only on your client and it looks you’re connecting using TLS 1.0 which is deprecated.
My proposed solution runs stunnel on your server and aims to implement a front end proxy to the imap/smtp product. This can give you the support for new TLS versions and no need to run stunnel on your clients.
No, I don't have access to the mail server machine. I just installed stunnel on a localhost VM, then lowered the VM minimum accepted TLS to 1.0, and then run Thunderbird from host machine. The latter will connect to the stunnel running in the VM