mirror/docker-mailserver.docker-mailserver
1
0
Fork 0
mirror of https://github.com/docker-mailserver/docker-mailserver.git synced 2025-06-24 17:58:58 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 3

Update README.md (#2425)

Browse source 
Co-authored-by: casperklein <casperklein@users.noreply.github.com>
This commit is contained in:
wolkenschieber 2022-02-21 12:05:39 +01:00 • committed by GitHub
parent b61dfe1e24
commit d858669dd4
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
3 changed files with 2 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

112
docs/content/examples/use-cases/forward-only-mailserver-with-ldap-authentication.md Normal file
View file

@ -0,0 +1,112 @@
---
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:
```env
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:
```sh
./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][github-issue-1247]. However if there are many user accounts, it is better to use authentication with LDAP. The settings for this on `mailserver.env` are:
```env
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:
```properties
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`][docs-userpatches]). I created the script `docker-data/dms/config/user-patches.sh`, with content like this:
```bash
#!/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.
[docs-userpatches]: ../../config/advanced/override-defaults/user-patches.md
[github-issue-1247]: https://github.com/docker-mailserver/docker-mailserver/issues/1247