Its always better to disable ssh access to root user which will protect the server from any attacks. Its kind of additional security layer on top of firewall.
There are 2 ways to disable SSH access to root.
In /etc/ssh/sshd_config file search for line DenyUsers, if it exists edit it as follows else add following line:
If you want to disable ssh login for multiple users on the server add as following:
DenyUsers root user1 user2 user3
After updating sshd_config add restart sshd service with following command:
$ service sshd restart
Now try to ssh to root, it should not allow login even though you entered right password.
PermitRootLogin will support 2 options “yes” and “no”.
Option yes will allow ssh to root and option no wont allow ssh to root.
To allow ssh to root add following line in /etc/ssh/sshd_config file and restart sshd service:
To disable ssh to root add following line in /etc/ssh/sshd_config file and restart sshd service:
In Ubuntu/Debian by default while creating ext2/ext3/ext4 file system 5% of disk space is reserved for super user across each partition.
Except for root partition 5% reserved space is not required for other partitions. So we reuse that reserved space.
We can reuse this reserved space with tune2fs command.
First get file system device path for which you want to reduce reserved space. Use df -h command to get the details:
$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda5 28G 4.7G 22G 18% /
udev 2.8G 4.0K 2.8G 1% /dev
tmpfs 1.2G 880K 1.2G 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 2.9G 2.2M 2.9G 1% /run/shm
/dev/sda7 311G 166G 131G 56% /home
To make only 2% space as reserved on /home use following command:
$ sudo tune2fs -m 2 /dev/sda7
In above command /dev/sda7 my file system device path for /home
Now check your space details with df -h and observe the size of /home partition it should be increased.
We can record and reply a terminal/konsole session with script command and reply it with scriptreply command.
Here is the example to record the session:
$ script -t 2> timing.txt -a session.txt
Script started, file is session.txt
Now you can start typing some commands.
$ echo "Hello world"
To stop recording run exit command.
In above session we ran echo, date commands, and stored output in timings.txt and session.txt
To replay recorded session use scriptreplay as shown below:
$ scriptreplay timing.txt session.txt
It will print/replay whole session that we recorded.