Dear All ,

Kindly I have some questions , I need hints or answers please .

I have sparc4 , sun solaries 7 , mail server . i have about 5000 users , with no login shell , or home directories for the users .

they only have mail boxes in /var/mail dir .

now , I do not have any type of back up , what is the easiest solution to take back up for my server , or lets say for my 5000 user info. and emails , is there a utility that i can use in order to backup !!

I know /etc/passwd , /etc/shadow and /etc/group files .

any advice ?!?!?

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i was thinking of a silly solution ,,, i do not know if i can apply it ,,, for example if i took ( copy ) , /etc/passwd , /etc/shadow and /etc/group files , then i installed a new server and pasted them again ,,, am i gunna get same users and passwd's ??



thanks

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Muhannad Tamemi

Hi Tamemi,

This is not a very stupid remark. As long as your users do not login the most important files are /etc/passwd, /etc/shadow and /etc/group. Of course your /var/mail directory would be important of course as well.

But, why don't you attach a simple backup-unit to the server. You take quiet a risk here !!

Else rebuilding the data on the other server each day using rsync could be a solution as well of course. Please know for sure that your server is not that important!

B.T.W. : tar could already be ok for the things you need, ufsdump is a more extensive program.

Regs David

what i need to be sure of ,, or what i understood from your answer , is that i can restore all users info. and passwords , if my existing server dropped down , and I set up a new one ??

i mean ( want to be sure of ) , can i have all users defined again , without manual defining !! redefining 5000 user ??

later on i will buy something llike tape in order to back up important files on it .

also i need to know , does ufsdump or tar , back up all emails in my users mail boxes ??

thanks

__________________
Muhannad Tamemi

Yes, you can for a hundred percent sure rebuild your users by simply making a copy of your passwd-files (passwd,shadow and group) I can asure you !!

A mailbox is nothing else than a simple flat file. So also yes, you can easily backup mailboxes. Please refer to the man-pages for details on how to backup the filesystems you want.

Regs David

now everyting is clear ..

Thanks .

Do you know i have another questions ,,, not related to back up !!


1. Why unix system could not be infected ith viruses !!

2. how can i stop many many spam emails , which are getting me and my users crazy !!

is there any FREE antispamm software that works with solaries7 , sendmail 8.9.3

Thanks

__________________
Muhannad Tamemi

Hi,

There definitly are multiple anti-spam progs. Please post a new question for this (In the Sun forum?). To be honest I am not an expert on that area, so you need the help of our friends.

Unix is different build than Windows. To explain it all might be a bit too much to explain. It's possible thought, but it's just not popular and is less easy to do.

Regs David

Unix is a collection of operating systems that run on any hardware. Unix people rarely download executables except from very trusted sources.

Windows users will download executables very frequently and virtually all of them use a cpu that uses intel's instruction set.

True viruses are machine specific. So you can create a SunOS true virus or an HP-UX true virus. But a unix true virus cannot be written.

The first internet based attack was the morris worm which targeted several versions of unix simultaneously. It took down many unix based systems. It even crossed over to Milnet and took down hundreds of military systems. That was well over 10 years ago and unix security has improved a lot since then.

Unix tends to treat email as something for a human to read. It is very rare for a unix system to attempt to execute an incoming email message automatically. It also helps that there are other operating systems that are very vulnerable to viruses. They divert the attention of virus authors away from unix. Finally, unix still has several security problems of its own. A cracker who wants to breech unix security will target one of those.

These are the big factors that act to protect unix from viruses. True viruses that is....

However, people use the term virus loosely. I know the difference between a virus and a worm. However, I would not be amused if the virus scanning software that I bought for my laptop intentionally ignored worms.

And evil software doesn't always perfectly match the classical definitions. Those email viruses that target windows are not true viruses. But it's not clear what to call them... they are sort of a cross between a trojan horse and a worm or something.

Now consider your mail server: if an email virus targeted toward Windows arrives on your server, it will not magically disappear. Sure, it won't affect your unix based mail server. That doesn't mean that you want to forward it to your user's computer. I would call a unix mail server waiting to download windows viruses "infected". What other term would you use? (Actually, I kinda like the term "subclinical infection".)

So unix can be infected with anything and after you loosen up the definition of "virus" enough to include all evil software, unix can be affected by viruses.

As for antispam, click on home, then click on answers to frequently asked questions, then click on email antispam techniques and email filtering