[mythtv-users] HDHR failing

Stephen Worthington stephen_agent at jsw.gen.nz
Sat Nov 14 02:51:18 UTC 2020

On Fri, 13 Nov 2020 17:46:02 -0700, you wrote:

>On Fri, Nov 13, 2020, 3:07 AM David Watkins <watkinshome at gmail.com> wrote:
>> ..or you could have a faulty Ethernet cable/connector or network switch.
>> To know how to troubleshoot this you need to understand your network a bit.
>Possible, but everything was working fine for a couple months then stopped
>working, and it's only mythbackend that can't access it.
>> How is your backend connected to the HDHR?  Wi-Fi or wired?  What other
>> things are on the network?
>Both are wired.  Other things on the network are the normal things, a
>desktop, a couple phones, a few echos, some smart switches.
>> What IP address do the HDHR and mythbackend have, and how are they
>> assigned?  They can be manually assigned or they can pick them up from a
>> device running DHCP (usually either a wifi access point or your ISP's
>> broadband modem/gateway).
>Backend has a static IP ( HDHR has a DHCP address
>(, currently).
>One sort of odd thing is that the HDHR is not showing up on the client list
>on my router.  However, like I said it works with other devices, I can ping
>it from the backend, and nmap shows it's up, connected, and working fine.

Have you set up the router to manually assign the HDHR's IP address?
If you have, that causes some routers to not list the manually
assigned IP addresses in the list of DHCP leases - they only list the
dynamically assigned addresses coming from the IP address pool.  If
the IP address is fully dynamic and assigned from the pool, that is a
bad idea as if it gets a new IP address mythbackend will likely never
find it again until mythbackend is restarted.  Mythbackend only finds
and initialises tuners at startup and has no mechanism for restarting
them in the case of problems.  So it would be a good idea to assign it
a manual address now if you need to.  Make sure the address is outside
the DHCP pool range - using one that is inside the pool range can
cause two devices to get the same IP address.  To get the HDHR to see
the manually assigned address, you may need to cycle its power and the
router's power as they can both remember the old IP address assignment
and may keep using it in preference to the new setting until they are
forced to forget it.

If that does not get things working, then ping the HDHR from the
MythTV box to get its IP address known to that PC, then use the "arp
-a" command to find the MAC address of the HDHR.  Or maybe the MAC
address is on the HDHR's label.  On the MythTV box, install tshark if

apt install tshark

and then run this command:

sudo tshark -tad -P -w eth0.pcap -i eth0 ether host <MAC address of

Adjust the "eth0" bits to the name of your Ethernet port if necessary.
Ping the HDHR again and check that tshark shows the ping.

Then restart mythbackend and tshark should see all the traffic it does
with the HDHR (if any).  That will also be stored to the eth0.pcap
file which can be loaded into Wireshark on any PC that has it
installed.  You can also make it available for us to look at if you
need help with working out what is going on.

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