Breaking the internet (hotels, guestnet style)

Suresh Ramasubramanian ops.lists at
Mon Dec 7 19:35:34 CST 2009

You could just firewall off port 25 and leave 587 open - to save
yourself from a bunch of viruses and such.
A lot of people will use webmail anyway - from a hotel.  And you avoid
getting blacklisted

The other option is to install a device that examines email flows and
allows only stuff it doesnt think is spammy (netflow for email kind
of, with all the bayesian etc secret sauce).
Two devices come to mind

* Symantec E160 (used to be called turntide, and before that, back in
2002-03, spam squelcher)
* Mailchannels (

There's probably a few more that do this and are totally transparent.

On Tue, Dec 8, 2009 at 6:54 AM, Andrew Cox <andrew at> wrote:
> I would be interested to hear what people have to say about this, as the
> only other option I could think of would involve checking the incoming
> connection to see if the end user was trying to authenticate to a mail
> server before determining where to forward the connection onto (Layer 7
> stuff, gets a bit tricky)

Suresh Ramasubramanian (ops.lists at

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