Hi all, Can the mailcow-dockerized be install in another location? Like /opt/mailcow-dockerized to /var/lib/docker/compose/mailcow. I am having some tls issues. I am not sure if that is the cause.

Make sure all requirements are met: https://docs.mailcow.email/getstarted/prerequisite-system/ And then check the logs: https://docs.mailcow.email/troubleshooting/debug-logs/

The directory where the stack is installed has absolutely nothing to do with TLS Maybe try describing your problem in detail

Hi all, I too found nothing in the documentation that mentions installation to other than /opt is not recommended so I believe it should be fine. Mailcow is working fine for clients on the newer machines (OS). We have an Oracle servers which can only work on TLS 1.1. I am planning to have the Oracle servers to send and receive emails using the Mailcow since we have moved the company emails to M365 which only accept TLS1.2 with some SMTP-AUTH requirements (mentioned by the MIS Team). I am having issues when connecting one of the Oracle server to Mailcow. When I tested the connection from another linux box using Openssl command line (openssl s_client -connect server:993 -tls1_1), I am getting error "no peer certificate available". My certificate is from LetsEncrypt. When I try the same command but point to port 443, it works fine. I do not the certificate error.

TLS 1.0 and 1.1 have been disabled some time ago. If you really need to enable this again see https://docs.mailcow.email/manual-guides/u_e-reeanble-weak-protocols/

Hi DocFraggle, I have enabled it at Postfix extra.cf and Dovecot extra.cf using the same documentation.

Why don't you install a simple Postfix on your Oracle servers which sends emails to a configured relay server? We did it this way at our company. Why would you want to install a full groupware stack just for Oracle servers to be able to send mails in the first place?

Yes, a groupware stack is an overkill. Just a postfix container like this does the trick: https://hub.docker.com/r/boky/postfix/

But the MIS Team refuses that method saying Oracle is mission critical for the company and changing anything to it may cause issue bla bla bla ........ Since we used to provide that service (On premise Exchange), my team should provide same method alternatives. Therefore I will not go down that path except for providing the alternative to my on premise exchange. When I ran the command "openssl s_client -starttls imap -connect mailserver:143 | openssl x509 -noout -text", I got the error below. Is there anything wrong with my setting? There is no issue when checking with port 587 and 443. **write:errno=104 unable to load certificate 140653554096016:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:707:Expecting: TRUSTED CERTIFICATE** Below is the result when I query the certificate expiry date. **echo | openssl s_client -connect mailserver:143 -starttls imap 2>/dev/null | openssl x509 -inform pem -noout -enddate | cut -d "=" -f 2 unable to load certificate 140126333908880:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:707:Expecting: TRUSTED CERTIFICATE** Below is the result when I query the certificate expiry date. ``` echo | openssl s_client -connect mailserver:143 -starttls imap 2>/dev/null | openssl x509 -inform pem -noout -enddate | cut -d "=" -f 2 unable to load certificate 140126333908880:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:707:Expecting: TRUSTED CERTIFICATE ``` Below is the result when I query the certificate expiry date. ``` echo | openssl s_client -connect mailserver:143 -starttls imap 2>/dev/null | openssl x509 -inform pem -noout -enddate | cut -d "=" -f 2 unable to load certificate 140126333908880:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:707:Expecting: TRUSTED CERTIFICATE ``` Below is the result when I query the certificate expiry date. echo | openssl s_client -connect mailserver:143 -starttls imap 2>/dev/null | openssl x509 -inform pem -noout -enddate | cut -d "=" -f 2 unable to load certificate 140126333908880:error:0906D06C_:PEM routines:PEM_read_bio:no start line:pem_lib.c:_707:Expecting: TRUSTED CERTIFICATE I got the same error when I query the certificate expiry date. echo | openssl s_client -connect mailserver:587 -starttls smtp 2>/dev/null | openssl x509 -inform pem -noout -enddate | cut -d "=" -f 2 I got the same error when I query the certificate expiry date. echo | openssl s_client -connect mailserver:587 -starttls smtp 2>/dev/null | openssl x509 -inform pem -noout -enddate | cut -d "=" -f 2 a Something went wrong in my earlier entry. Checking on how to edit it

Hi all,

DocFraggle

Question 1: why are you trying to connect to IMAP? IMAP is for receiving mail with an IMAP client. I thought you want to send mail? Try port 25 of your mailcow
Question 2: which OS are you running your Oracle databases on? We use RedHat, installed the Postfix package, configured it to use Exchange as relay and Oracle is sending mails via localhost:25

Azard

For question 1, that was how the communication was made to the old on premise exchange. I will confirm this again.
For question 2, they are using unix.

Azard

Oracle will send out approval email where the department head will respond. Oracle will the check the emails in the mailbox for the approvals and proceed with the next process.

Azard

I am getting this error in Dovecot;

dovecot-mailcow-1 | Sep 24 08:24:34 ad03f9862894 dovecot: master: Dovecot v2.3.21.1 (d492236fa0) starting up for imap, sieve, lmtp, pop3
dovecot-mailcow-1 | Sep 24 08:24:34 ad03f9862894 dovecot: doveadm: Error: SSL context initialization failed, disabling SSL: Can’t set cipher list to ‘ALL:!ADH:!LOW:!SSLv2:!!SSLv3:!EXP:!aNULL:!3DES:!MD5:!PSK:!DSS:!RC4:!SEED:!IDEA:+HIGH:+MEDIUM’ (ssl_cipher_list setting): error:0A000118:SSL routines::invalid command
dovecot-mailcow-1 | 2024-09-24 08:24:35,239 INFO success: processes entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)
dovecot-mailcow-1 | 2024-09-24 08:24:35,239 INFO success: dovecot entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)
dovecot-mailcow-1 | 2024-09-24 08:24:35,239 INFO success: syslog-ng entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)

DocFraggle

OK, I know what the “problem” is:

71f2e63f09c1:/# openssl version
OpenSSL 3.3.1 4 Jun 2024 (Library: OpenSSL 3.3.1 4 Jun 2024)

The dovecot container (and the postfix container as well) are using OpenSSL version 3. TLS 1.0 and 1.1 support has been removed completely. So unfortunately no chance for you to use TLS 1.0 and 1.1 with mailcow

@DerLinkman @pkernstock I think it would be best to add a note or completely remove the page at

https://docs.mailcow.email/manual-guides/u_e-reeanble-weak-protocols/

DerLinkman

DocFraggle Were did you read that?

@Azard What are your dovecot settings?

Did you modified dovecot’s extra.cf? The error is coming during boot. That is not a “normal” behaviour

Azard

Thank you for the update. Is there an older version of mailcow that supports TLS 1.1 I can fallback to?

On a side note, smtp over port 465 works fine though. Only imap over port 143 has issue.

DocFraggle

Azard smtp over port 465 works fine

But your still can’t use tls 1.1 though

Azard Is there an older version of mailcow that supports TLS 1.1 I can fallback to

You could manually checkout the repo with an older tag, but I wouldn’t recommend this

DocFraggle

DerLinkman Were did you read that?

I have to rephrase, it wasn’t removed completely, but:

SSL 3, TLS 1.0, TLS 1.1, and DTLS 1.0 only work at security level 0, except when RSA key exchange without SHA1 is used.

See https://openssl-library.org/news/openssl-3.0-notes/index.html at the bottom.

You need to switch to security level 0 by editing the openssl.cnf file like described here:

https://stackoverflow.com/questions/77812112/what-to-do-if-cipherstring-defaultseclevel-1-in-openssl-3-configuration-file

But I didn’t test it. A fact is, that without adjusting the OpenSSL config, you can’t enable TLS 1.0 and 1.1 just by editing the extra.conf files as described in https://docs.mailcow.email/manual-guides/u_e-reeanble-weak-protocols/ with the current containers which use Openssl 3.x

Azard

DerLinkman I did the same as mentioned in the documentation to support TlS1.1.

ssl_min_protocol = TLSv1

DerLinkman

DocFraggle You can. For me it works…

DocFraggle

DerLinkman not working with my dovecot container:

3f7553eb96e7:/# doveadm config get ssl_min_protocol
ssl_min_protocol = TLSv1

3f7553eb96e7:/# openssl s_client -connect 127.0.0.1:993 -tls1_1 -brief
Connecting to 127.0.0.1
28FBC15DEB7F0000:error:0A0000BF:SSL routines:tls_setup_handshake:no protocols available:ssl/statem/statem_lib.c:153:

while trying TLS 1.2 works as expected

3f7553eb96e7:/# openssl s_client -connect 127.0.0.1:993 -tls1_2 -brief
Connecting to 127.0.0.1
Can't use SSL_get_servername
CONNECTION ESTABLISHED
Protocol version: TLSv1.2
Ciphersuite: ECDHE-RSA-AES256-GCM-SHA384
Peer certificate: CN=mail.domain.tld
Hash used: SHA256
Signature type: RSA-PSS
Verification: OK
Supported Elliptic Curve Point Formats: uncompressed:ansiX962_compressed_prime:ansiX962_compressed_char2
Server Temp Key: X25519, 253 bits
* OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE LITERAL+ AUTH=PLAIN AUTH=LOGIN] Dovecot ready.

This really works on your mailcow instance?

EDIT: after applying this inside the dovecot container it works:

sed -i '/\[openssl_init\]/a ssl_conf = ssl_configuration' /etc/ssl/openssl.cnf

echo "[ssl_configuration]" >> /etc/ssl/openssl.cnf \
    && echo "system_default = tls_system_default" >> /etc/ssl/openssl.cnf

echo "[tls_system_default]" >> /etc/ssl/openssl.cnf \
    && echo "MinProtocol = TLSv1" >> /etc/ssl/openssl.cnf \
    && echo "CipherString = DEFAULT@SECLEVEL=0" >> /etc/ssl/openssl.cnf

Now the output is:

3f7553eb96e7:/# openssl s_client -connect 127.0.0.1:993 -tls1_1 -brief
Connecting to 127.0.0.1
Can't use SSL_get_servername
CONNECTION ESTABLISHED
Protocol version: TLSv1.1
Ciphersuite: ECDHE-RSA-AES256-SHA
Peer certificate: CN=mail.domain.tld
Hash used: MD5-SHA1
Signature type: RSA
Verification: OK
Supported Elliptic Curve Point Formats: uncompressed:ansiX962_compressed_prime:ansiX962_compressed_char2
Server Temp Key: X25519, 253 bits
* OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE LITERAL+ AUTH=PLAIN AUTH=LOGIN] Dovecot ready.

But this change isn’t persistent after updates of the container

DerLinkman

Ok, i see. Yeah sorry.

Then we’ll patch that openssl option into dovecot, coming with next update.

Postfix btw too!

DocFraggle

Is there a way to let Docker override the openssl.cnf file somehow instead? So that only in the very very rare cases where someone really wants to use TLS < 1.2 he can add his own openssl.cnf file? I’m not sure if patching the file for all of us leads to a security risk, i.e. the next OpenSSL downgrade attack or something like that

Azard

My oracle servers manage to communicate with the mail server using STARTTLS via port 143. I applied the settings provided by DocFraggle. I also need to modify the ciphers in /etc/dovecot/dovecot.conf. However I still facing issue using TLS via port 993. Still looking at it. Thank you all

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