IPv4-only frontend cannot connect to dual-stack backend

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eypo
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IPv4-only frontend cannot connect to dual-stack backend

Post by eypo » Thu Jan 28, 2021 12:28 pm

Here is the setup:

- Computer running mythtbackend on ubuntu 20.10, dual stack (ipv6 and ipv4). DNS properly configured (A and AAAA records).
- Computer running mythfrontend on ubuntu 20.10, ipv4 only.
- Computer running mariadb 10.5 on debian 10, dual stack just like mythbackend.

All computers belong to same IPv4 subnet and same LAN, firewalls disabled. Backend and database belong to same IPv6 subnet too.

If I fire up mythfrontend, it does connect to database, retrieves FQDN of backend (masterIP and masterIP6 both contain backend's FQDN) and resolves it to IPv6, then it tries to connect to that IPv6 address and of course fails (as IPv6 is not configured in frontend). It retries several times, but it never uses ipv4.

Error shown (repeated several times) is:
2021-01-28 13:18:05.870 I MythCoreContext::ConnectCommandSocket(): Connecting to backend server: 2001:XXXX:1f13:55f::70:6543 (try 1 of 1)
2021-01-28 13:18:05.871 E MythSocket(7f5d4c006310:-1): Failed to connect to (2001:XXXX:1f13:55f::70:6543) Network unreachable
2021-01-28 13:18:05.871 E Connection to master server timed out.
Either the server is down or the master server settings
in mythtv-settings does not contain the proper IP address

Tried in mythtv/31 and mythtv/32. Same result.

Of course, enabling IPv6 on frontend, or disabling IPv6 in backend (and correcting settings in database) solves this.

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stuarta
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Re: IPv4-only frontend cannot connect to dual-stack backend

Post by stuarta » Fri Jan 29, 2021 1:59 pm

The workaround is to set the backend address to the ipv4 address via setup

eypo
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Re: IPv4-only frontend cannot connect to dual-stack backend

Post by eypo » Fri Jan 29, 2021 3:06 pm

stuarta wrote:
Fri Jan 29, 2021 1:59 pm
The workaround is to set the backend address to the ipv4 address via setup
:o :(

So, fixing this bug is out of question, right?

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stuarta
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Re: IPv4-only frontend cannot connect to dual-stack backend

Post by stuarta » Tue Feb 02, 2021 10:23 am

eypo wrote:
Fri Jan 29, 2021 3:06 pm
So, fixing this bug is out of question, right?
Nope, we like to fix bugs. Just offering suggestions to get things working for you until such time as we can get to it.

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stuarta
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Re: IPv4-only frontend cannot connect to dual-stack backend

Post by stuarta » Tue Feb 02, 2021 10:31 am


eypo
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Re: IPv4-only frontend cannot connect to dual-stack backend

Post by eypo » Tue Feb 02, 2021 10:36 am

stuarta wrote:
Tue Feb 02, 2021 10:23 am
eypo wrote:
Fri Jan 29, 2021 3:06 pm
So, fixing this bug is out of question, right?
Nope, we like to fix bugs. Just offering suggestions to get things working for you until such time as we can get to it.
Reading again my post, now it sounds quite rude. I'd like to apologize.

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stuarta
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Re: IPv4-only frontend cannot connect to dual-stack backend

Post by stuarta » Tue Feb 02, 2021 10:36 am

eypo wrote:
Tue Feb 02, 2021 10:36 am
stuarta wrote:
Tue Feb 02, 2021 10:23 am
eypo wrote:
Fri Jan 29, 2021 3:06 pm
So, fixing this bug is out of question, right?
Nope, we like to fix bugs. Just offering suggestions to get things working for you until such time as we can get to it.
Reading again my post, now it sounds quite rude. I'd like to apologize.
No problem!

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