Verified the bug on SSSD Version: sssd-1.15.2-50.el7_4.2.x86_64

Steps followed during verification:

1. Setup sssd.conf as mentioned in https://bugzilla.redhat.com/show_bug.cgi?id=1464049#c0

2. login as ldap user in SSSD client machine and wait for over a minute.

3. Monitor NSS and PAM file descriptors on a different terminal.

With the latest sssd build, the count of FD's has come down to one. Earlier with old build we use to see more than 2 idle connections.

[root@idm-qe-01 ~]# lsof -p $(pidof sssd_nss) | grep /var/lib/sss/pipes/nss
sssd_nss 30620 root   17u     unix 0xffff8801fefcb400       0t0     56264 /var/lib/sss/pipes/nss
[root@idm-qe-01 ~]# 
[root@idm-qe-01 ~]# lsof -p $(pidof sssd_pam) | grep /var/lib/sss/pipes/pam
sssd_pam 30621 root    0u     unix 0xffff8800e0a16800       0t0     57000 /var/lib/sss/pipes/pam
[root@idm-qe-01 ~]# 
[root@idm-qe-01 ~]# lsof -p $(pidof sssd_nss) | grep /var/lib/sss/pipes/nss
sssd_nss 30620 root   17u     unix 0xffff8801fefcb400       0t0     56264 /var/lib/sss/pipes/nss
[root@idm-qe-01 ~]# 
[root@idm-qe-01 ~]# lsof -p $(pidof sssd_pam) | grep /var/lib/sss/pipes/pam
sssd_pam 30621 root    0u     unix 0xffff8800e0a16800       0t0     57000 /var/lib/sss/pipes/pam

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2017:2574