Horton

Re: A vexing problem with LDAP

Laurenz Albe <laurenz.albe@cybertec.at>

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From: Laurenz Albe <laurenz.albe@cybertec.at>
To: "Subramanian,Ramachandran" <ramachandran.subramanian@alte-leipziger.de>, "pgsql-novice@lists.postgresql.org" <pgsql-novice@lists.postgresql.org>
Date: 2026-03-13T07:04:19Z
Lists: pgsql-novice 
On Fri, 2026-03-13 at 06:57 +0000, Subramanian,Ramachandran wrote:
> We have an USERID ( VALID-USER)  who exists in the LDAP Group G_APP_Postgres_Users. 
>  
> PS H:\> Get-ADUser -LDAPFilter "(&(objectClass=user)(sAMAccountName=VALID-USER)(memberOf=CN=G_APP_Postgres_Users,OU=Anwendungen,OU=Gruppen,OU=Identity,DC=my-Konzern,DC=de))"
>  
> DistinguishedName : CN=VALID-USER,OU=Konten,OU=EWT,OU=PostgreSQL,OU=Ressourcen,DC=my-Konzern,DC=de
> Enabled           : True
> GivenName         : REWT-PostgreSQL
> Name              : VALID-USER
> ObjectClass       : user
> ObjectGUID        : 5a45f8e9-f13b-4ff2-9815-ec85bd0aeb7c
> SamAccountName    : VALID-USER
> SID               : S-1-5-21-4249930229-1474557206-4077294858-125360
> Surname           : Rochade-Konfig
> UserPrincipalName :VALID-USER@my-konzern.de
>  
> However when he tries to connect to postgres we see this error message.
>  
> Postgres-Log
> LOG:  LDAP user "VALID-USER" does not exist
> FATAL:  LDAP authentication failed for user "VALID-USER"
>  
> PG_HBA.CONF entry is shown below.
>  
> pg_hba.conf
> host   all             all              0.0.0.0/0             ldap ldapserver=ldap.my-konzern.de ldapport=389 ldapbinddn="CN=Postgres-LDAP,OU=Konten,OU=PROD,OU=PostgreSQL,OU=Ressourcen,DC=my-konzern,DC=de" ldapbindpasswd="dF3@3#s$P1" ldapbasedn="OU=Postgres,OU=Ressourcen,DC=my-konzern,DC=de" ldapscheme=ldap ldapsearchfilter="(&(objectClass=user)( sAMAccountName=%u)(memberOf=CN=G_APP_Postgres_Users,OU=Anwendungen,OU=Gruppen,OU=Identity,DC=my-konzern,DC=de))"
>  
> What could be the source of this error?

I'd say that because PostgreSQL <> Postgres, you won't find user
"CN=VALID-USER,OU=Konten,OU=EWT,OU=PostgreSQL,OU=Ressourcen,DC=my-Konzern,DC=de"
under the base distinguished name "OU=Postgres,OU=Ressourcen,DC=my-konzern,DC=de".

Try with ldapbasedn="OU=PostgreSQL,OU=Ressourcen,DC=my-Konzern,DC=de".

> How to debug this problem step by step to see where exactly the chain is disconnected?

Copy and paste is your friend, it avoids typos.

Yours,
Laurenz Albe