Setting up OpenBSD's LDAP Server (ldapd) with StartTLS and SASL

Published on 8/25/2017

OpenBSD has its own LDAP server, ldapd. Here’s how to configure it for use with StartTLS and SASL authentication

I don’t cover common LDAP operations, like adding users, as that’s covered well elsewhere

Server (ldapserver / 10.0.2.35)

Create a self-signed TLS certificate

# cd /etc/ldap/certs
# openssl genrsa -out ldapserver.key 2048
# openssl req -x509 -new -key ldapserver.key -out ldapserver.crt -days 365
# `# enter ldapserver as the canonical name`

Configure ldapd:

# touch /etc/ldapd.conf
# chmod o-r /etc/ldapd.conf 
# cat /etc/ldapd.conf

schema "/etc/ldap/core.schema"
schema "/etc/ldap/inetorgperson.schema"
schema "/etc/ldap/nis.schema"

listen on lo0 tls certificate ldapserver  
listen on em0 tls certificate ldapserver
listen on "/var/run/ldapi"

Check your configuration:

# /usr/sbin/ldapd -n
configuration ok

Enable and start ldapd:

# rcctl enable ldapd
# rcctl start ldapd
ldapd(ok)

Copy the cert to /tmp so we can scp it as not root from the client:

cp /etc/ldap/certs/ldapserver.crt /tmp

Need to debug ldapd?

# /usr/sbin/ldapd -d -vv
# ldapctl log verbose

Client

Trust the server’s certificate:

# echo '10.0.2.35    ldapserver' >> /etc/hosts
# scp notRoot@ldapserver:/tmp/ldapserver.crt >> /etc/ssl/trusted.crt

Install openldap-client (this installs cyrus-sasl as well):

# pkg_add openldap-client

Configure it:

# cat /etc/openldap/ldap.conf
TLS_CACERT    /etc/ssl/trusted.crt

Start saslauthd

# rcctl enable saslauthd
# rcctl start saslauthd
saslauthd(ok)

Connect to ldapd (-ZZ means force TLS, use -H to specify URI):

# ldapsearch -H ldap://ldapserver -ZZ
SASL/PLAIN authentication started
Please enter your password:

Need to debug saslauthd?

# /usr/local/sbin/saslauthd -a getpwent  -d

Need to debug OpenLDAP client?

# ldapsearch -d1 -v -ZZ
# ldapadd -d1 -v -ZZ

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