error while installing openssh-serer

unable to make backup link of `./usr/sbin/sshd' before installing new version: Operation not permitted

 

open terminal:

sudo su

Check the attributes of /usr/bin/ssh:

lsattr /usr/bin/ssh

root@purval-pc:~# lsattr /usr/bin/ssh
su--ia------------ /usr/bin/ssh
root@purval-pc:~#

 

If you see the attributes i and a, remove them both:

chattr -i /usr/bin/ssh
chattr -a /usr/bin/ssh

If you just see i or a, remove just the one you see.

 Now do the same again for /usr/bin/sshd:

lsattr /usr/bin/sshd

root@server1:~# lsattr /usr/bin/sshd
su--ia------------ /usr/bin/sshd
root@server1:~#

 

If you see the attributes i and a, remove them both:

chattr -i /usr/bin/sshd
chattr -a /usr/bin/sshd

 

and reboot the server

reboot