RHCSA- Questions with Verified Solutions
how do you grab a kerberos keytab from a server? Correct Ans-wget -O /etc/krb5.keytab
http://classroom.example.com/pub/keytabs/<yourkeytab>.keytab
explain the difference between wget, wget -O and wget -O-. Correct Ans-wget <url> will pull
a file with whatever filename it has. -O <filename> <url> names the file it pulls in. -O- pulls to
stdout.
how would you specify kerberos with integrity checking in fstab for an nfs share? Correct
Ans-sec=krb5i instead of "defaults"
list the contents of serverX's smb share. Correct Ans-smbclient -L //serverX
mount serverX's smb share in your filesystem. authenticate to the share as a guest. use a
command. Correct Ans-mount -t cifs -o guest //serverX/share /<mountpoint>
won't work unless you've created the mount point already with mkdir.
how does a smb share show up in fstab? Correct Ans-//serverX/share /mountpoint cifs guest
00
,mount serverX's smb share in your filesystem. authenticate to the share as a user with the most
secure method possible. use a command. Correct Ans-mount -t cifs -o
credentials=/secure/<user> //serverX/<share> /<mountpoint>
where /secure/<user> contains:
username=<un>
password=<pw>
domain=<dn>
what's the difference between autofs for smb and nfs? Correct Ans-both require subconfigs
under auto.master.d ending in .autofs formatted as <mountpoint> /etc/auto.<share>
/etc/auto.<share> needs to be formatted as:
<sharename> -fstype=cifs,credentials=/secure/<credsfile> ://serverX/<remoteshare>
what package has to be installed for smb to work? Correct Ans-cifs-utils
what's the recommended permissions for a secure creds file for smb authentication? Correct
Ans-0600
give an overview of the boot process. Correct Ans-1) post
2) bios loads
, 3) mbr partitions checked for bootloader location
4) grub2 bootloader takes over loads os selection, waits for user
5) filesystem read on selected os, kernel loaded in memory and initialized
6) systemd loads and checks fstab
7) fstab devices are mounted, and the system is remounted on /sysroot, the kernel takes over
8) systemd looks for default target (graphical, emergency, etc) and launches to it.
how can you set a default systemd boot target? Correct Ans-systemctl set-default
<target>.target
bonus: what does rd.break actually do? Correct Ans-pauses the system before the initramfs
boot process hands off control to systemd. the prompt you get after rd.break is an initramfs
debug shell.
bonus: what does chroot do? what's a chroot jail? why use it? Correct Ans-changes the
apparent root of the filesystem tree. a chroot jail is an execution environment for a process that
doesn't allow it access to the full filesystem. it's used to isolate non-root processes from the
operating system.
bonus: why do you need to run touch /.autorelabel when doing the break-in? Correct Ans-
because passwd recreated /etc/shadow without any selinux context.
how do you grab a kerberos keytab from a server? Correct Ans-wget -O /etc/krb5.keytab
http://classroom.example.com/pub/keytabs/<yourkeytab>.keytab
explain the difference between wget, wget -O and wget -O-. Correct Ans-wget <url> will pull
a file with whatever filename it has. -O <filename> <url> names the file it pulls in. -O- pulls to
stdout.
how would you specify kerberos with integrity checking in fstab for an nfs share? Correct
Ans-sec=krb5i instead of "defaults"
list the contents of serverX's smb share. Correct Ans-smbclient -L //serverX
mount serverX's smb share in your filesystem. authenticate to the share as a guest. use a
command. Correct Ans-mount -t cifs -o guest //serverX/share /<mountpoint>
won't work unless you've created the mount point already with mkdir.
how does a smb share show up in fstab? Correct Ans-//serverX/share /mountpoint cifs guest
00
,mount serverX's smb share in your filesystem. authenticate to the share as a user with the most
secure method possible. use a command. Correct Ans-mount -t cifs -o
credentials=/secure/<user> //serverX/<share> /<mountpoint>
where /secure/<user> contains:
username=<un>
password=<pw>
domain=<dn>
what's the difference between autofs for smb and nfs? Correct Ans-both require subconfigs
under auto.master.d ending in .autofs formatted as <mountpoint> /etc/auto.<share>
/etc/auto.<share> needs to be formatted as:
<sharename> -fstype=cifs,credentials=/secure/<credsfile> ://serverX/<remoteshare>
what package has to be installed for smb to work? Correct Ans-cifs-utils
what's the recommended permissions for a secure creds file for smb authentication? Correct
Ans-0600
give an overview of the boot process. Correct Ans-1) post
2) bios loads
, 3) mbr partitions checked for bootloader location
4) grub2 bootloader takes over loads os selection, waits for user
5) filesystem read on selected os, kernel loaded in memory and initialized
6) systemd loads and checks fstab
7) fstab devices are mounted, and the system is remounted on /sysroot, the kernel takes over
8) systemd looks for default target (graphical, emergency, etc) and launches to it.
how can you set a default systemd boot target? Correct Ans-systemctl set-default
<target>.target
bonus: what does rd.break actually do? Correct Ans-pauses the system before the initramfs
boot process hands off control to systemd. the prompt you get after rd.break is an initramfs
debug shell.
bonus: what does chroot do? what's a chroot jail? why use it? Correct Ans-changes the
apparent root of the filesystem tree. a chroot jail is an execution environment for a process that
doesn't allow it access to the full filesystem. it's used to isolate non-root processes from the
operating system.
bonus: why do you need to run touch /.autorelabel when doing the break-in? Correct Ans-
because passwd recreated /etc/shadow without any selinux context.
