Hulu / ESPN: Commercial IP Address

Stuart Henderson stu at
Mon Oct 15 14:19:02 UTC 2018

On 2018-10-15, Brandon Butterworth <brandon at> wrote:
> On Sat Oct 13, 2018 at 02:39:37PM -0400, Daniel Corbe wrote:
>> I had a customer with a similar issue.   I statically assigned them a  
>> different IP and it didn???t resolve it.   The problem turned out to be 
>> tied  to their Hulu account.
> I had a similar issue with wifi calling on O2 in the UK. it
> worked on some wifi but not others. After pressing O2 support
> for quite some time they admitted "you're on commercial IP space
> which we don't support" but would say no more.
> After a little puzzling I realised the working wifis were
> NATed to 1918 so I added NAT to one that wasn't working and the
> phone registered OK for wifi calling. The address it was NATed
> to was the same range so it appears their test is for 1918 space
> on the client.

Wifi calling (and femtocells and UMA) use IPsec. If NAT is detected
(rewriting just the port number is probably enough) it will trigger
using UDP encapsulation, without NAT perhaps they are trying to do ESP
and they've blocked that somewhere.

They usually have geolocation / ISP whitelists too, presumably to stop
people trying to use it to get around roaming charges. (I've also seen
a Vodafone femtocell do something funny with frequent NTP packets
which makes me suspect they may do latency checks sometimes as well).

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