Listen host:port is useless unless you also listen to the local interface

[michaelrsweet]

Version: 1.1.19rc5
CUPS.org User: peter.mathiasson

Using Listen is useless unless you also listen to the same port using your local interface (127.0.0.1).

eg.
Port 631
Listen ipp.example.com:80

When use your webbrowser and goto ipp.example.com/printers; and none shows up.

[michaelrsweet]

CUPS.org User: mike

This is a side-effect of how the authentication information must be passed from the CGI programs; if they didn't use the localhost interface then you wouldn't be able to perform any operation that required authentication.

We'll add documentation to the Listen directive in the SAM concerning this...

[michaelrsweet]

CUPS.org User: peter.mathiasson

Couldn't it be configured to always connect to localhost to port 631 for instance?

That way, even though I connect to my ethernet interface (ipp.example.com) on port 80, the local communcation could still be performed, if I had at least one port open on the local interface.

[michaelrsweet]

CUPS.org User: mike

No, since not everyone runs CUPS on port 631.

[michaelrsweet]

CUPS.org User: peter.mathiasson

I meant make it a configuration option.

[michaelrsweet]

CUPS.org User: mike

That's the whole point; all you need to do is tell cupsd to listen on localhost as well as the specific address, so there already is a configuration directive...

[michaelrsweet]

CUPS.org User: peter.mathiasson

What I want is something along the line with the patch I just posted. I don't know if this will break anything, perhaps you can tell me?

[michaelrsweet]

CUPS.org User: peter.mathiasson

Should read if (LocalPort) and not if (LocalPort && ServerName) though.

[michaelrsweet]

CUPS.org User: peter.mathiasson

Better tell you why would I like to do this.
I want to have apache listening on the local interface on port 80 and 443.

[michaelrsweet]

CUPS.org User: mike

We won't apply the patch to the core CUPS release, as we don't want to add another configuration directive that has limited usefulness.

However, we will look at automatically using the first port that is bound to the loopback address or to the "any" address instead of the connecting port, which will do the same thing without manual configuration and will work with current configurations without changes.

[michaelrsweet]

CUPS.org User: peter.mathiasson

Yes, you're right. That's a much better idea. I've posted a new patch.

[michaelrsweet]

CUPS.org User: mike

We're looking at your patch now to make sure that it functions properly on all architectures; the comparison to 0x7f000001 needs to use the ntohl macro/function since the network address is always in network byte order (big endian) and the integer will be in local byte order...

[michaelrsweet]

CUPS.org User: mike

Fixed in CVS; we chose to cache the port in StartListening since the port numbers don't change unless you reconfigure...