There is some information from the Debian wiki (
https://wiki.debian.org/LDAP/PAM)
on adding a host attribute to a user, but I'm sure it applies to
other distro's as well:
To
add the "host"
attribute to a user, he should have an objectClass that
supports this. The "account"
objectClass has the attribute, but is not compatible with
the "inetOrgPerson"
objectClass. To work
around this, you can use the "ldapns" schema,
supplied with the libpam-ldap package. This
schema provides the "hostObject"
objectClass, which has the proper "host"
attribute.