squid

i have 5 servers in my network
i want to put a firewall between servers and LAN
my users gatway will be squid firewall
and i want to creat some access lists who has access and who doesnt

yes definitely you can do this you can do this in 3 ways

ACL on IP
ACL on User
ACL on MAC Address

Tell me have u setup squid allready? if so tell me your present configuration.

i havent setup yet, just planning to setup, anyway thanks
i will choose squid
does it also have bandwidth management ip based?

Take a look at below example

acl My_Computer1 src 192.168.0.1
acl My_Computer2 src 192.168.0.10
http_access deny My_Computer1
http_access deny My_Computer2


My_Computer1 and My_Computer2 are the ACL names (you can use any name)

In the above example you are blocking the access to both the IPs. You can further simply the above 4 lines in just 2 steps

Yes almost everything is possible in Squid except pop3 and smtp since squid is purely http proxy

If you need any further help you can post here

for example i have a server with windows update and sql running
i want a user to be able to access windows update service, and deny to sql
is it possible as well?