I'm using CentOS 5.0,5.1, and 5.2 on several systems where I'm seeing this problem. Hello, I'm seeing a weird problem that perhaps someone has run into with groups. First, a little background. I was made aware of a problem with CentOS 5 where if the nscd password cache is clear and someone tries to log in if there is no network connection with an LDAP account that it just hangs. Even worse, if the machine is rebooted and it continues to have no network connection, even root login doesn't work. I messed around with nsswitch.conf to fix this problem. I altered these lines as so: passwd: files [!NOTFOUND=return] ldap shadow: files [!NOTFOUND=return] ldap group: files [!NOTFOUND=return] ldap and the problem seemed to go away. But now, here's the weird stuff: I have defined in my local /etc/groups file this line: group1:x:100:apache group2:x:101:apache 'getent group groupname' shows the right info: # getent group group1 group1:x:100:apache # sudo -u apache bash $ groups apache I revert back to my old config: # sudo -u apache bash $ groups apache group1 group2 Also, something else that's interesting. If I do this: passwd: files [!NOTFOUND=return] ldap shadow: files [!NOTFOUND=return] ldap group: ldap [NOTFOUND=continue] files and reboot, udev segfaults and the system freezes up after a few more seconds. Starting udev: /sbin/start_udev: line 43: 519 Segmentation fault "$@" $ARGS /sbin/start_udev: line 201: 523 Segmentation fault /sbin/udevd -d Wait timeout. Will continue in the background.[FAILED] Any advice?