UNIX for Dummies Questions & Answers

Hi, I am extremely new to UNIX and was recently promoted to administer the system for a small company. Anyhow, the time came for passwords to change, and I made the huge mistake of entering in the command (as root)

passwd -l

After logging out (oblivious to what would happen next), the root account could no longer be accessed. After researching why, I've discovered that the "-l" command locks out the account. After hours of searching the internet, the most common (and possbily only) solution is

1. boot UNIX into Single-User Mode
2. mount
3. edit passwd file
4. reboot

The only problem is I am so new to UNIX, I don't even know how to boot into Single-User Mode. I've tried typing in the following commands while logged in as a normal user

boot -s OR
init S

The UNIX box returns an error message saying that access is denied to the boot and init commands. I believe these are commands that only a superuser can access, and root was the only superuser on this particular system. To make matters worse, the old system administrator left things in a shamble. I have no boot disk; all I have is what I believe to be possible backups to the software that our company uses. I am running UNIX System V, if that helps.

Any help or feedback would be greatly appreciated. Thanks!

What is your platform type?

This brief simple & clear summury will get you out of trouble:

http://www.unixguide.net/unixguide.pdf

Thanks guys, you've been a great help. I've managed to drudge up an old boot disk and edit my passwd file. Needless to say, there will be another super user added on, and I will be more careful. Thanks again!!

When you say " another super user" I hope you dont mean adding a 2nd root account to the passwd file with 0 UID.

This can present many problems, not the least of which is when you do userdel -r root2 and remove all files owned by root... DONT DO THIS!!!!

Make sure at least you and your supervisor or backup has the root password as well as access to the machine incase of the "You get hit by a bus" syndrome...


Since you are new, here are a few security tips.....

I would also remove any users who are old or havent logged in since 6 months, or used to have root but no longer work there. this prevents any coworkers who may have had their password from logging in as another user.

Limit permissions on or remove .rhosts files in users' home directories... this gives equivalency on other boxes, as that user without a password.

I would suggest using the /etc/hosts.allow and /etc/hosts.deny files as well... to prevent unwanted remote access via open ports.

Use these as a template. You must have these loaded for each line to be valid.

# cat /etc/hosts.allow
#all : all : banners=/usr/localcw/opt/sysguard/banners : allow
ftpd : all : banners=/usr/localcw/opt/sysguard/banners : allow
telnetd : all : banners=/usr/localcw/opt/sysguard/banners : allow
tftpd : all : banners=/usr/localcw/opt/sysguard/banners : allow
logind : all : banners=/usr/localcw/opt/sysguard/banners : allow
rlogind : all : banners=/usr/localcw/opt/sysguard/banners : allow
remshd: all : banners=/usr/localcw/opt/sysguard/banners : allow
sidftpd : all : banners=/usr/localcw/opt/sysguard/banners : allow
rexecd : all : banners=/usr/localcw/opt/sysguard/banners : allow
sshd : all : banners=/usr/localcw/opt/sysguard/banners : allow

# cat /etc/hosts.deny
# Deny all hosts
ALL : ALL


Also, shutdown any services you dont need... such as many of the R*commands, rcp, rlogin, .rhosts...