[bind10-dev] use domain port 53

[Jeremy C. Reed]

On Tue, 1 Mar 2011, Michal 'vorner' Vaner wrote:

> On Tue, Mar 01, 2011 at 10:12:15AM -0600, Jeremy C. Reed wrote:
> > I understand there is a concern about doing this now due to not being 
> > able to listen to specific interfaces or something like that.
> 
> That is not the concern (actually, once #575 and #576 are reviewed, 
> it's not even true).

Thank you.

> The concern is that if something or your system lives on the port (not 
> unlikely), the components won't start up. They just crash on startup, 
> telling you the ports can't be used.

I think that is okay behavior. That is normal.

But existing problem where bind10 continues to restart it forever is a 
problem.

[b10-auth] Server failed: Failed to initialize network servers: Address 
already in use

(again and again!)

> But you can't reconfigure them, because they are not running.

That is a problem, I agree.

> So we need to either:
> ? Default to listening to nothing (users need to configure the thing 
> anyway), which is safe.

A resolver should be able to work by default without configuration.

> ? Allow editing configuration when the component isn't running.

We do need that.

> ? Don't completely die when the ports can't be bound.
> 
> I don't know about you, but I don't want to explain users they need to 
> turn off their dns server (as root) to be able to start a testing 
> instance of bind10 as regular user on different port than 53. It just 
> sounds wrong.

I believe the audience for that is way less than 1%. Most of the users 
will want to know why they can't use their DNS server using standard 
port automatically.

Example of the existing failure is:

> config set Resolver/listen_on [{ "address": "127.0.0.1", "port": 53}]
> config commit
[b10-cmdctl] Begin send command 'set_config' to module 'ConfigManager'
[b10-resolver] New config comes: { "listen_on": [ { "address": 
"127.0.0.1", "port": 53 } ] }
[b10-resolver] Setting listen addresses:
[b10-resolver]  127.0.0.1:53
[b10-resolver] Initialize TCP server at 127.0.0.1:53
[b10-resolver] Unable to set new address: Failed to initialize network 
servers: Address already in use
[b10-resolver] error in config: Failed to initialize network servers: 
Address already in use
[b10-cmdctl] Finish send command 'set_config' to module 'ConfigManager'
Error: Failed to initialize network servers: Address already in use
Configuration not committed


I think the above failure is acceptable (in the odd case something 
already using that port) except in the case where the server component 
keeps restarting continually (because configuration already existed). I 
don't think it is acceptable that I need to do a configuration step in 
the first place.