Restrict access to a single client device

[Ram]

On 02/01/2013 01:20 AM, Dale J Chatham wrote:
> You use SMTP authentication through postfix or sendmail.  Google [ mail
> authentication relay   ] and you should find lots of howtos.
>
> I'm setting it up to use a sasldb to authenticate external users in
> order to keep them apart from UNIX users.  Be very certain that you use
> STARTTLS or some form of authentication for email.  Also, if you're
> allowing internet access to e-mail, you'll want to use imaps or https.
The idea is that end users configure their email  on Desktop, Laptop , 
Phone , tablet, Ipad ... ( The list is getting longer every day )
So copies of the mail are floating everywhere.

This raises a security concern

I cant block access totally from outside.
Employees should be allowed access from outside office , but only from 
the designated Laptop.
One way would be to ask everyone to VPN to the office for mails , Is 
there anyway else.


Thanks
Ram