[CentOS] Postfix: user unknown

[nate]

Manuel Monteiro wrote:
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> Dear all,
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>
>
> I have a mail server based on  a CentOS 5.3 machine with postfix.
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>
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> Most of our users are on LDAP (on localhost) but we also have some local
> users and we are using PAM for authentication.

Are you running nscd on the server? That should smooth out LDAP
blips, though I would disable nscd's dns caching in /etc/nscd.conf

Is postfix configured to talk directly to LDAP ? What does the
configuration look like?

nate