See Red Hat Bugzilla bug #846852 for details. https://bugzilla.redhat.com/show_bug.cgi?id=846852 FYI: We discovered that after updating to EL 6.3 on our x86_64 server, autofs 5.0.5-54 broke our nightly backups that rely on automounting an NFS share hosted on another EL 6 machine on our local network. The machine hosting NFS server was configured to allow only TCP connections to the port specified by MOUNTD_PORT in "/etc/sysconfig/nfs" Any attempts to access this share caused segmentation faults in the automount daemon. EL 6.2 hosts that had not yet been updated had no problems accessing the same NFS shares. While testing we found that opening the UDP MOUNTD_PORT on the NFS server firewall allowed successful access to the NFS shares from the EL 6.3 NFS client without segfault. Closing the port caused the EL 6.3 NFS client to return to the faulty behavior. On another fully updated EL 6.3 i386 host, we were able to duplicate the same symptoms. On one of the EL 6.2 hosts not yet updated we confirmed no issues with the previous autofs package, then upgraded only autofs. After the upgrade we confirmed symptoms identical to the fully updated 6.3 machines. While filing the bug report I found 2 other, possibly related, bugs written against autofs 5.0.5-54 that did not describe our symptoms but may be relevant to other users on this list. Bug 840025 - autofs 5.0.5-54 fails to mount share on IPv6 netapp https://bugzilla.redhat.com/show_bug.cgi?id=840025 Bug 834641 - autofs requires portmapper on server for NFSv4 mounts https://bugzilla.redhat.com/show_bug.cgi?id=834641 [Workaround] For now, we are leaving the UDP NFS port open on the firewall of the NFS server. Our networks are completely isolated from the outside world so this doesn't pose a significant risk. However, this may not be acceptable for everyone's environment.