[mythtv-users] setting up a AirTV Anywhere tuner with MythTV

[Stephen Worthington]

On Fri, 24 Jun 2022 16:01:02 -0500, you wrote:

>On Fri, Jun 24, 2022 at 2:36 PM James Abernathy <jfabernathy at gmail.com>
>wrote:
>
>>
>>
>> On Fri, Jun 24, 2022 at 2:23 PM Greg Oliver <oliver.greg at gmail.com> wrote:
>>
>>> On Fri, Jun 24, 2022 at 1:14 PM James Abernathy <jfabernathy at gmail.com>
>>> wrote:
>>>
>>>>
>>>>
>>>> On Fri, Jun 24, 2022 at 12:05 PM Greg Oliver <oliver.greg at gmail.com>
>>>> wrote:
>>>>
>>>> Everything spunds like it should work - you just need the commands to
>>>>> tune it, which Sling obviously sends it.  Once those commands are
>>>>> discovered, you should have no issues.  I am asuming Sling can also use it
>>>>> to watch liveTV.
>>>>>
>>>>> -Greg
>>>>>
>>>>
>>>> Your assumption is correct.  In fact my use case at this point is for
>>>> liveTV watching only. It allows for quick switching from ESPN to CBS OTA
>>>> for example.
>>>>
>>>> Can anyone recommend a good software tool for capturing packets for a
>>>> particular IP address?
>>>>
>>>> Jim A
>>>>
>>>
>>> tcpdump on any linux box will suffice.  If you can get the IP of Sling as
>>> well as AirTV, then a filter would be:
>>>
>>> tcpdump -i <ethernet interfce> -nn -s0 -w dump.cap host <ip of AirTV> or
>>> host <ip of Sling>
>>>
>>> after that, the dump.cap file can be opened in Wireshark to filter
>>> through it.
>>>
>>>
>> Sorry for the dumb question but here goes.  The -i option must be the
>> device name for my wifi on my laptop, right? that interface will not see
>> any packets addressed to it to/from the AirTV.
>>
>> when I did:  sudo tcpdump -i wlp0s20f3 -nn -s0 -w dump.cap host
>> 192.168.0.154
>> I started watching OTA tv on which should have caused traffic between the
>> AirTV 192.168.0.154 and my FireTV stick 192.168.0.107.
>>
>> But when I ctrl-c'ed to stop tcpdump, it captured 0 packets.  Which sort
>> of makes sense because the laptop is on 192.168.0.122
>>
>> Can the laptop act like a monitor and watch the traffic? All my devices
>> are on 192.168.0.xx
>>
>> Jim
>>
>
>Yeah - you need a switch that can port mirror traffic and/or use an
>ethernet hub (not switch) to get in the middle of the transactions.  Either
>way, you would need ethernet on your laptop if they are not on wireless.

It is also possible to set up a "man in the middle" PC which connects
to the device you are trying to see the traffic from and bridges that
traffic to the subnet it is normally supposed to go to.  But that
requires a higher level of networking expertise, and two network
interfaces.  It is much easier to do with Ethernet than WiFi, but then
requires two Ethernet ports.  It really gets complicated if you need
to have the same subnet IP addresses being used on two network ports
of the same PC - you have to use network namespaces to isolate the two
networks from each other.  But I have been able to do that when I
spent a day working it all out.