Breaking the internet (hotels, guestnet style)

Joel Esler eslerj at
Mon Dec 7 23:13:15 CST 2009

On Dec 7, 2009, at 10:18 PM, Lou Katz wrote:

> On Mon, Dec 07, 2009 at 09:48:25PM -0500, Steven Bellovin wrote:
>> On Dec 7, 2009, at 6:00 PM, Jared Mauch wrote:
>>> On Dec 7, 2009, at 5:29 PM, John Levine wrote:
>>>>> Will be interesting to see if ISPs respond to a large scale thing like
>>>>> this taking hold by blocking UDP/TCP 53 like many now do with tcp/25
>>>>> (albeit for other reasons). Therein lies the problem with some of the
>>>>> "net neturality" arguments .. there's a big difference between "doing it
>>>>> because it causes a problem for others", and "doing it because it robs
>>>>> me of revenue opportunities".
>>>> I do hear of ISPs blocking requests to random offsite DNS servers.
>>>> For most consumer PCs, that's more likely to be a zombie doing DNS
>>>> hijacking than anything legitimate.  If they happen also to block
>>>> that's just an incidental side benefit.
>>> I've found more and more hotel/edge networks blocking/capturing this traffic.
>>> The biggest problem is they tend to break things horribly and fail things like the
>>> oarc entropy test.
>>> They will often also return REFUSED (randomly) to valid well formed DNS queries.
>>> While I support the capturing of malware compromised machines until they are
>>> repaired, I do think more intelligence needs to be applied when directing these systems.
>>> Internet access in a hotel does not mean just UDP/53 to their selected hosts plus TCP/80,
>>> TCP/443.
>> It's why I run an ssh server on 443 somewhere -- and as needed, I ssh-tunnel http to a squid proxy, smtp, and as many IMAP/SSL connections as I really need...

Also handy to set up an SSH tunnel.  That works for almost everything else.


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