Cool Solution - Install ProFTP and setup ldap authentication

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Produktlogo UCS Version 3.2
Note: This article is not yet reviewed.


Introduction

Large environments may manage users centrally using a LDAP database. You can configure ProFTP service to do password/UID/GID lookups from an LDAP, instead of simple files as in the default configuration. This article describes how to connect ProFTPD with the domain's LDAP. After completing these steps, users can log in to the FTP server with their UCS domain username and password.


Preparation

For the installation to succeed, some packages must be downloaded from the Univention unmaintained repositories. To activate the Univention unmaintained repository, execute the following command:

ucr set repository/online/unmaintained=yes

Hint: Unmaintained packages are not covered by security updates.

Installation

To install the ProFTP daemon on a system, the package univention-ftp must be installed either using the UMC module or by executing the following command in a command line shell:

univention-install univention-ftp proftpd-mod-ldap

Configuration

The ProFTP daemon must load its LDAP module. Edit the file /etc/proftpd/modules.conf and remove the # in front of the line LoadModule mod_ldap.c

Also edit the file /etc/proftpd/proftpd.conf and remove the # in front of the line Include /etc/proftpd/ldap.conf

Next a simple authentication account should be created using UDM. This account can then be used for an authentication bind.

udm users/user create --set username=proftpd-user --set lastname="ProFTPD Service" --set password="p4Ss-W0rd"

The new DN will be shown afterwards. To find the DN of the account, issue the following command on the command line:

udm users/user list --filter username=<NAME of the account> | grep DN

In the LDAP configuration file /etc/proftpd/ldap.conf use the following settings:

# Only use LDAP Auth
AuthOrder                       mod_ldap.c
<IfModule mod_ldap.c>
LDAPServer <fqdn of the DC master>:7389
LDAPDNInfo "<DN of the authentication account>" "<Password of the authentication account>"
# Get user info (dn, uid, gid)
LDAPDoAuth on "cn=users,$ldap_base"
# GID to name in dir listing
LDAPDoGIDLookups on "cn=groups,$ldap_base"
# UID to name in dir listing
LDAPDoUIDLookups on "cn=users,$ldap_base"
LDAPUseTLS on
# Create homedir if not exists
CreateHome on 711 skel /etc/skel
LDAPGenerateHomedir on
</IfModule> 

Hint: change $ldap_base according to the domain to use. The domain can be obtained by executing ucr get ldap/base in a command line shell.

Hint: if you want your home directorys with other permissions, change the octal value at CreateHome.

Note: ldap.conf file supports mod_ldap options at version 2.8.22

Open ports in the Firewall

To accept connections via the FTP port on your FTP Server, you need to open the ports 20 and 21. For that it is best practice to create a package filter rule instead of a local filter rule

ucr set security/packetfilter/package/univention-ftp/tcp/20/all=ACCEPT
ucr set security/packetfilter/package/univention-ftp/tcp/21/all=ACCEPT

Not necessary but recommended is a description for your new created filter rule(s).

ucr set security/packetfilter/package/package/protocol/port(s)/all/en=<DESCRIPTION>

After all changes have been made, the univention-firewall and the proFTP server have to be restarted

invoke-rc.d univention-firewall restart
invoke-rc.d  proftpd restart

Known Issues

FileZilla

If you want to connect to your proFTP Server via FileZilla, FileZilla usally connects in passive mode (server based). This may lead to an error when FileZilla tries to list the directory.

To fix this, you have to enable the passive ports in your /etc/proftpd/proftpd.conf config. To enable the passive ports, uncomment the following line

# PassivePorts                  49152 65534

and define a port range that suits your network configuration.

Following the ports have to be opened in the univention-firewall. To open a port range, seperate the first and the last port with a colon (:)

ucr set security/packetfilter/package/univention-ftp/tcp/<start port>:<end port>/all=ACCEPT

Afterwards, restart the univention-firewall

invoke-rc.d univention-firewall restart

Now, the authentication via FileZilla using passive ports should be working.


Further links

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