function of Postfix,clamav,mailscanner and spamassassin adn which server require it
 

Can anyone please tell me in which servers(i.e mail,ftp,web,primary and slave nameservers) should we be installing clamav,mailscanner,postfix and spamassassin?

I researched and went through google as well but it's really confusing me because i thought these were supposed to be used in mail server especially postfix and mailscanner but i didn't find it that way...i found postfix in slave name server running centOS...

So can anyone please clarify my doubt?

YOUR HELP WOULD BE HIGHLY APPRECIATED..

Im not expert in that but seen somewhat obvious that clamav goes with email and maybe with ftp if users are allowed to upload files, mailscanner and spamassassin(if it is used to check spam mail) with email. Postfix sounds like have something to do with email, (post, posting...).
I may be wrong cos im just guessing but spamassassin sound to me it can be used also in the web server if it does have a chat service running.

http://spamassassin.apache.org/
http://www.postfix.org/
http://www.clamav.net/
http://mailscanner.info/

Regards

Just trying to understand your question, so hope this is right. Postfix, mailscanner, clamav and spamassassin are installed on a mail server, also known as a email server. You can install these on servers that also have other programs like web, ftp etc running on them.

well i went through those sites and it isn't helping much...m still confused..

OK your a bit confused, can you give some more information, do you have to setup a mail server and your researching it is confusing you on how to go about it?

well i am not setting up a mail server, it's already there but i need to work with it so wanted to know what needs to b there and when i checked other servers(i.e dns servers) i was really confused because i saw postfix,clamav,mailscanner and spamassassin all here n there and didnt find postfix in mail server so found that really confusing.

My guesstimate whoever installed it the server in the place:

a. put package selection on default which puts additional packages
b. was testing some mail setup on the dns

Regardless, if you're certain the server serves only DNS, then it would be safe to remove the "confusing" packages. Of course, make sure you have a backup first before removing packages off a live server.

Now getting a better understanding of your situation, you already have the sever setup and you have to work on it. If Postfix is not there, another will be installed, Postfix is not the only mail server software, there are others like Sendmail, Qmail, Exim, Courier, Dovecot.