[mythtv-users] [Q] : Why only numeric IP addresses work?

[Ray Olszewski]

Just to be clear at the outset ... this really is not a MythTV problem. It 
is a problem with your Linux networking setup, one that would affect a lot 
of apps, and should be fixed at that level, not worked around via 
trickiness with /etc/hosts or somesuch.

Still, you do want to get it fixed.

To get help with it (either here or on a help list for your distro), you 
need to explain the setup in enough detail that someone can help you spot 
the bug. Even if an interface is not connected to a LAN, it should still be 
possible, trivially easy really, to bring it up (assign it an IP address 
and related stuff). To figure out why your backend's eth0 is not coming up, 
please tell us:

1. How the backend is connected to the LAN. As Adam asked, does it connect 
to a hub, or do you connect and disconnect the laptop directly (using a 
crossover cable)? Or is a WiFi setup involved? Or something else (what?)?

2. What eth0 is. Is it a standard NIC of some sort, or something unusual?

3. What Linux distro and version you are using.

4. Even if the interface it not "up" (configured), it should still exist. 
Check this with "ifconfig -a" or (I think) "ip link show".

5. If your Linux is tolerably standard, it uses "ifup eth0" to bring up 
that interface. What happens if you run that command (as root) from the 
command line? (If you get an error response, please quote it exactly. If 
you don't, quote the relevant portion of the output of "ifconfig" or "ip 
addr show" after you run it.) If your distro brings up interfaces a 
different way, do whatever is appropriate to bring up eth0 via the command 
line and tell us the result, as above.

6. How the desktop host's IP address is being assigned. Finding the answer 
is a bit distro specific, but checking for its stanza in 
/etc/network/interfaces is a likely place to start. Meaningful answers to 
this question are "static" and "dhcp" ... if the second, where is the DHCP 
server it gets its lease from?

7. Some interpretations of what you've said so far imply that this backend 
is a standalone system with no connection to the Internet. Or, just 
possibly, the laptop acts its route to the Internet (if it has 2 interfaces 
and an appropriate configuration to route or bridge). Please clarify this 
part, if prior answers do not already make it clear. (If it is isolated, 
how does it use Myth? What do you do about listings?)

At 11:22 AM 2/19/2004 -0600, Adam Biskobing wrote:
>Do you have your laptop connected directly to your backend server?  Is
>it not going through a switch/hub?
>
> > -----Original Message-----
> > From: mythtv-users-bounces at mythtv.org
> > [mailto:mythtv-users-bounces at mythtv.org] On Behalf Of manu
> > Sent: Thursday, February 19, 2004 11:11 AM
> > To: Discussion about mythtv
> > Subject: Re: [mythtv-users] [Q] : Why only numeric IP addresses work?
>[...]
> > Thanks for your detailed answer. Here is the thing : for a
> > reason I am
> > still investigating eth0 will be up automatically only if the
> > laptop is
> > also plugged, which is a bug in my config I agree. But then
> > this leads
> > me to try to put the name of the master backend in myth setup
> > so that
> > as you also said, an alias in the hosts file would resolve to
> > localhost
> > even if the lan is down. Then the local frontend can connect to the
> > backend as expected (whateverup or down the LAN is) BUT the remote
> > frontend cannot connect to the backend anymore. This is somewhat
> > weird : the remote frontend will only connect if the master
> > backend is
> > in numeric form in the setup. Whereas for instance the
> > mysql.txt file
> > of my remote frontend as the name of my backend not the
> > numeric IP and
> > it works nice.
> > Bye
> > Manu