[Fedora-directory-users] ldap too many connections from clients? following ldap even for local accounts?

[George Holbert]

> If a machine is disconnected from the network, a login attempt as 
> 'root' user (with local passwd file entry and password) fails.
> ...
> I think I need to configure something such that the nsswitch.conf 
> entry tells it to stop if it finds the 'files' entry and not proceed 
> to the 'ldap' entry.  I thought this would happen by default.

At least for authentication, this behavior depends also on your PAM config.

You need to make sure that the auth and account stacks will succeed for 
local accounts (e.g., root) without asking pam_ldap.
What's in your /etc/pam.d/system-auth files on your RHEL3 and RHEL4 clients?


MJD Shop Account wrote:
>  I'm having some odd ldap issues with connection or lack thereof to 
> ldap server when nsswitch.conf and pam.d/system-auth are configured to 
> used FDS ldap server.
>
> I'm running both RHEL3 and RHEL4 clients.  My servers are RHEL4 update 
> 4 and FDS 1.0.4.  My /etc/ldap.conf is configured with two host 
> names.  I've noticed these issues:
>
>     * If a machine is disconnected from the network, a login attempt
>       as 'root' user (with local passwd file entry and password)
>       fails.  The system appears to accept the password, but sits for
>       maybe a minute, then dumps you back to the login prompt.  I've
>       had to  boot off rescue CD and shell in to remove 'ldap' from
>       the /etc/nsswitch.conf file to get around this in some instances.
>
>       My relevant /etc/ldap.conf entries are:
>       passwd:     files ldap
>       shadow:     files
>       group:      files ldap
>       netgroup:   files ldap
>
>     * I noticed that a anhy randomly chosen client has a few
>       connections to the ldap server that persist.  The connections
>       are tied to processes that also should have local entries only
>       in the local /etc/passwd files.  Here's an example:
>       # netstat -a | grep ldap
>       tcp       38      0 clienthostname:32771 serverhostname:ldap
>       CLOSE_WAIT 
>       # fuser 32771/tcp
>       here: 32771
>       32771/tcp:            3729
>       # ps -ef | grep 3729 | grep -v grep
>       ntp       3729     1  0 Feb23 ?        00:00:00 ntpd -u ntp:ntp
>       -p /var/run/ntpd.pid -g
>       #
>
>     * I notice that doing a "netstat -a" on the server that most
>       clients are using takes a long time.  It spits out a  bunch,
>       then slows down when reporting the entries that are ESTABLISHED
>       ldap connections:
>       tcp        0      0 ldapserver:ldap ldapclient:35908 ESTABLISHED
>       I see that some clients have very many connections, I would
>       expect just one or two.  Here's one client that had a whole
>       bunch, most disappeared before I could capture this bash shell
>       command output.  This output is for jobs associated with ports
>       connecting to ldap server:
>       # for i in `netstat -a | grep ldap | cut -d: -f2 | cut -d" "
>       -f1`; do for j in `(fuser $i/tcp | cut -b 23-26)`; do ps -ef |
>       grep $j | grep -v grep; done; done
>       xfs       2726     1  0 Feb20 ?        00:00:00 xfs -droppriv
>       -daemon
>       root      3138  3031  0 Feb20 ?        00:00:00
>       /usr/bin/gdm-binary bell-style none
>       root      3418  3138  0 18:32 ?        00:00:02 /usr/X11R6/bin/X
>       :0 -auth /var/gdm/:0.Xauth vt7
>       gdm       3430  3138  0 18:32 ?        00:00:00 /usr/bin/gdmgreeter
>       root      2477  2617  0 18:22 ?        00:00:01 sshd: root at pts/0
>       root      2481  2477  0 18:22 pts/0    00:00:00 -tcsh
>
>       I ran a similar command on a client computer where the user is
>       running a lot of jobs, I got 53 lines of output.  Basically
>       every job is maintaining an ldap connection, I guess.
>
>     * I think I need to configure something such that the
>       nsswitch.conf entry tells it to stop if it finds the 'files'
>       entry and not proceed to the 'ldap' entry.  I thought this would
>       happen by default.
>
>     * I think the above problem is possibly leading to many more ldap
>       connections than are necessary which in turn may be causing
>       performance issues on the server, ALTHOUGH the cpu load and
>       memory load does not appear inordinately heavy
>
>     * I tried running nscd (for caching the info) once, it seemed to
>       cause too many problems so I turned it off.  I have tried
>       something like implementing pam_ccache, I don't think it would
>       help the too-many-connections, just the issue with no logins
>       when off the net.
>
>     * Here's my /etc/ldap.conf minus the usual comment lines, I'm
>       doing anonymous binds.  Maybe there's some  keepalive flag that
>       should be set or unset?:
>       host server1 server2
>       base dc=example,dc=com
>       ldap_version 3
>       scope sub
>       bind_timelimit 10
>       pam_lookup_policy yes
>       pam_password exop
>       nss_base_passwd         ou=People,dc=example,dc=com?one
>       nss_base_group          ou=Group,dc=example,dc=com?one
>       nss_base_services       ou=Services,dc=example,dc=com?one
>       nss_base_aliases        ou=Aliases,dc=example,dc=com?one
>       nss_base_netgroup       ou=Netgroup,dc=example,dc=com?one
>       ssl start_tls
>       tls_checkpeer yes
>       tls_cacertfile /usr/share/ssl/certs/servercert.pem
>       tls_ciphers TLSv1
>       pam_password md5
>
> Any suggestions on what I might be doing  wrong are greatly appreciated!
>
> -Marty
>
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