[cups-devel] CUPS running on alternative port and alternative domain socket: Access via localhost restricted

[Till Kamppeter]

On 10/12/2016 06:12 PM, Till Kamppeter wrote:
>> There are some tricks that libcups uses to switch to the domain socket
>> for local access when port 631 is specified, which would bypass PAM
>> and the authentication stuff.  But the same will not happen when
>> connecting to port 10631.
>>
>
> Probably this is the reason why this happens.
>
> Could you modify the trick from localhost:631 being replaced by the
> domain socket to localhost:<port on which current cupsd is running>
> being replaced by the domain socket? This way CUPS would be completely
> consistent.

Now I have looked deeper into it and it seems that this cannot get 
changed, as the libcups cannot know which domain socket belongs to which 
CUPS daemon if there is more than one CUPS daemon 9AFAIK one cannot send 
a request to CUPS via localhost:port and get back the path of the domain 
socket, or is this possible?).

So I will have to use "-h <domain socket>" to access the other cupsd. 
And in the end the CUPS snap will also run on port 631, using the 10631 
port is only temporarily to not need to stop the local CUPS daemon.

Thank you very much for clarifying what happened here.

    Till