Re: Blocking email through the web services

["Martin Peikert" <Martin.Peikert () discon de>]

Nieveler, Juergen wrote:
> > > Is there a common port I can block that will prevent users from 
> > > downloading email from webmail services such as aol, 
> >
> > hotmail or msn, used by all - without blocking www service in general?
> >
> > Try port 110 (pop3), 995 (pop3-ssl) and maybe 220 (imap3) and 993 
> > (imap3-ssl), too.
>
> That won't help - he's talking about Web-based services, and those go
> through port 80/443.

Right - my mistake. But blocking those ports would make those services a 
little more uncomfortable ;-) The users have to log in in their webmail 
account and download one message after another instead of receiving them 
all at once...

> The only chance is to block file downloads on the proxy-server - and even
> that won't work if the Webmail service offers SSL.

Or, as Paul D. Robertson mentioned before, block those services offering 
webbased mail services. But to find out all those offering webbased mail 
- that's not that easy :-(

GTi

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