I can only testify for the stuff that I have used.
Since I have my core skills in other areas then Linux infrastructure – I have researched and decide to use Zentyal.
Therefore, all the suggestions I can provide you here are based on my experience and understanding of this suite.
Zentyal essentially wraps all sorts of Linux services under a nice web-front end that facilitates the administration of these services (http://doc.zentyal.org/en/presentati...erver-for-smbs
). These are still running on Linux, thus you are able to manually amend these configuration if you wish.
About your Setup:
Enabling site-to-site connectivity and fault tolerance
since you have two sites to work with; you can have two Zentyal installation working as GATWAYS (one in each site), and set a VPN between them, thus allowing for traffic between office to be exchanged securely (http://doc.zentyal.org/en/vpn.html#c...s-with-zentyal
These gateways can support connection redundancy to ensure 100% up-time. In this case you can have two or more broadbands/mobile connections. This will not only support uninterrupted connectivity but also increased throughput (http://doc.zentyal.org/en/routing.ht...g-with-zentyal
the Zentyal gateways come with a firewall module which is fantastic.
As a bonus you can also use proxy (transparent) to speed up and filter web access, with exception to HTTPS. Rules can be create for group or individual users. (http://doc.zentyal.org/en/proxy.html...g-with-zentyal
And it also have Intrusion detection system (http://doc.zentyal.org/en/utm.html
As much as I Trust Zentyal, I always prefer to use an installation with simple Ubuntu Server LTS.
And that is it. Just create a DMZ with the Firewall/Gateway above and keep it separated from your internal network.
You can continue hosting your email externally, it might a way of keeping it safe in a way.
Since you will have two sites with fault tolerance connections to the web, you might consider hosting your emails with zentyal (I have been using Zentyal for the past 3.5 years); but this is only an option if you have two servers ensuring 100% uptime. They also support sieve rules.
I am not sure Zimlet alone is a CRM solution – there are open-source ones; I have a friend who uses TigerV – http://www.insidecrm.com/features/to...utions-121307/
but really this is more of a business decision then technical. You would need to do an assessment to discovered what is currently needed and will be needed in the medium term (3-5 yrs). Since it is such a specialist area you might to consider buying it with support.
Domain Controller & User administration
Zentyal used LDAP to create user accounts in the PDC (primary domain controller.
With 2 sites you can have a PRIMARY and SLAVE domain controllers that synchronised automagically for you (http://doc.zentyal.org/en/directory.html
file-sharing uses Samba, which also can provide printing services to windows clients. With Windows clients correctly setup with Zentyal, their home partitions are mounted from the Zentyal server on to H: .
with users making use of Zentyal storage you then backup all data securely and encrypted with duplicity (http://duplicity.nongnu.org/
), all under Zentyal web-interface.
Zentayl provides the above solution as it is as an open-community option as well as a commercially supported solution.
In this way you can purchase their support while you get your self acquainted with Linux while supporting their development.
As a commercial customer, you cal also use their remote monitoring system which enables you to check on all your servers state.
Things that you need to check
this is the stuff that I am not quite sure about your setup or how Zentyal will fit into it.
clients Window 7, please check with Zentyal if they are already supporting win7 to the extent you need (eg: remote users – road-warrior scenario)
use x32 bit on the email server as there is a problem with Virus Scanning on the x64 bit of Ubuntu Server
need to check how access to Samba/Email Server can be maintained, if connection to main site fails
Suggestions for your installation
These are the Zentyal entities that you might need in each site.
1 Master LDAP
1 Samba/Email Server
1 Storage Server for holding backups
connected to 2 different broadband providers that do not use the same infrastructure (some use BT's); thus you might need to look for BT and Virgin as they have different physical infrastructure.
2 fast NIC access for internal network
using VPN setup to allow connectivity between sites
holds the LDAP database ONLY – does not need much storage but needs to be reliable
requires large storage and fast NIC access
1 Storage Server for holding backups
requires large disk storage to accommodate backup of Samba/Email Server
1 Slave LDAP
1 Slave Samba/Email
same as above
using VPN connection in gateway, connects to Master LDAP and copy users' details
using VPN connection in gateway, syncs with Master Samba/Email
Hope the above serves as a starting point of how to use Zentyal as a solution to your needs.
You can clarify further, by posting in their forums or dropping an email to them directly.
If I can help further them, please let me know.