Default system users

Hello

I have a question

I have this users on my aix 5.3 box. This are a default users.

lp::11:11::/var/spool/lp:/bin/false
invscout::6:12::/var/adm/invscout:/usr/bin/ksh
snapp::200:13:snapp login user:/usr/sbin/snapp:/usr/sbin/snappd
ipsec::201:1::/etc/ipsec:/usr/bin/ksh
nuucp::7:5:uucp login user:/var/spool/uucppublic:/usr/sbin/uucp/uucico
sshd::202:201::/var/empty:/usr/bin/ksh

My question is. I cant lock this users. for that nobody can use them.

One of the reasons its because they dont have a password. and for the books Im reading there is no problem with this users.

But I would like to know your opinions.

Thanks in advance

lp allows you to use printers, so if you want to allow users to print using lp then don't block the user.

Each of those has a use, like sshd for being able to connect using ssh, for example.

What makes you require that they have to be locked?

The principal reason its for security. that I want to lock this user account.

But I would to hear your opinions.

Thanks again