fb72f3ad52
Using `set -ex` will exit the script as soon as a non-zero exit code is returned, such as when the docker image fails building the docs due to `build --strict` catching broken links. This also removes the need for `|| exit` when changing directory. This seems fine for a small script, but AFAIK an alternative fix is just adding `|| exit` to the end of the `docker run` command too? There appears to be advice [against adopting `-e` carelessly](http://mywiki.wooledge.org/BashFAQ/105), while others [encourage `-e`](http://redsymbol.net/articles/unofficial-bash-strict-mode/). I know that several maintainers here have preference towards `set -e` so I've kept the original PR solution. Additionally: - `-x` is used to improve command visibility when reviewing the workflow log output. - `--name` isn't necessary, but was part of the original PR. - I've chosen not to include `-o pipefail`, only because no pipes are used in this script. * docs(fix): Fix broken links * ci(docs): Added inline docs Extra documentation context for maintainers to quickly grok what's going on. * chore(docs): Minor typo fix by wernerfred Added from their related PR by request.
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| title |
|---|
| Use Cases | Forward-Only Mail-Server with LDAP |
Building a Forward-Only Mail-Server
A forward-only mail-server does not have any local mailboxes. Instead, it has only aliases that forward emails to external email accounts (for example to a Gmail account). You can also send email from the localhost (the computer where docker-mailserver is installed), using as sender any of the alias addresses.
The important settings for this setup (on mailserver.env) are these:
PERMIT_DOCKER=host
ENABLE_POP3=
ENABLE_CLAMAV=0
SMTP_ONLY=1
ENABLE_SPAMASSASSIN=0
ENABLE_FETCHMAIL=0
Since there are no local mailboxes, we use SMTP_ONLY=1 to disable dovecot. We disable as well the other services that are related to local mailboxes (POP3, ClamAV, SpamAssassin, etc.)
We can create aliases with ./setup.sh, like this:
./setup.sh alias add <alias-address> <external-email-account>
Authenticating with LDAP
If you want to send emails from outside the mail-server you have to authenticate somehow (with a username and password). One way of doing it is described in this discussion. However if there are many user accounts, it is better to use authentication with LDAP. The settings for this on mailserver.env are:
ENABLE_LDAP=1
LDAP_START_TLS=yes
LDAP_SERVER_HOST=ldap.example.org
LDAP_SEARCH_BASE=ou=users,dc=example,dc=org
LDAP_BIND_DN=cn=mailserver,dc=example,dc=org
LDAP_BIND_PW=pass1234
ENABLE_SASLAUTHD=1
SASLAUTHD_MECHANISMS=ldap
SASLAUTHD_LDAP_SERVER=ldap.example.org
SASLAUTHD_LDAP_START_TLS=yes
SASLAUTHD_LDAP_BIND_DN=cn=mailserver,dc=example,dc=org
SASLAUTHD_LDAP_PASSWORD=pass1234
SASLAUTHD_LDAP_SEARCH_BASE=ou=users,dc=example,dc=org
SASLAUTHD_LDAP_FILTER=(&(uid=%U)(objectClass=inetOrgPerson))
My LDAP data structure is very basic, containing only the username, password, and the external email address where to forward emails for this user. An entry looks like this:
add uid=username,ou=users,dc=example,dc=org
uid: username
objectClass: inetOrgPerson
sn: username
cn: username
userPassword: {SSHA}abcdefghi123456789
email: external-account@gmail.com
This structure is different from what is expected/assumed from the configuration scripts of docker-mailserver, so it doesn't work just by using the LDAP_QUERY_FILTER_... settings. Instead, I had to use a custom configuration (via user-patches.sh). I created the script docker-data/dms/config/user-patches.sh, with content like this:
#!/bin/bash
rm -f /etc/postfix/{ldap-groups.cf,ldap-domains.cf}
postconf \
"virtual_mailbox_domains = /etc/postfix/vhost" \
"virtual_alias_maps = ldap:/etc/postfix/ldap-aliases.cf texthash:/etc/postfix/virtual" \
"smtpd_sender_login_maps = ldap:/etc/postfix/ldap-users.cf"
sed -i /etc/postfix/ldap-users.cf \
-e '/query_filter/d' \
-e '/result_attribute/d' \
-e '/result_format/d'
cat <<EOF >> /etc/postfix/ldap-users.cf
query_filter = (uid=%u)
result_attribute = uid
result_format = %s@example.org
EOF
sed -i /etc/postfix/ldap-aliases.cf \
-e '/domain/d' \
-e '/query_filter/d' \
-e '/result_attribute/d'
cat <<EOF >> /etc/postfix/ldap-aliases.cf
domain = example.org
query_filter = (uid=%u)
result_attribute = mail
EOF
postfix reload
You see that besides query_filter, I had to customize as well result_attribute and result_format.
!!! note "See also"
For more details about using LDAP see: [LDAP managed mail-server with Postfix and Dovecot for multiple domains](https://www.vennedey.net/resources/2-LDAP-managed-mail-server-with-Postfix-and-Dovecot-for-multiple-domains)
!!! note
Another solution that serves as a forward-only mail-server is [this](https://gitlab.com/docker-scripts/postfix).
!!! tip
One user reports only having success if `ENABLE_LDAP=0` was set.