Comment 16 for bug 1598300
Revision history for this message
| Till Kamppeter (till-kamppeter) wrote Re: cups hang after a while | #16 |
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Not having "ListenStream=631" in the systemd cups.socket file is intended. See the answer from Mike Sweet, author of CUPS:
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First, the reason why we don't include "ListenStream=631" is because that exposes cupsd to remote attack. And we don't listen on localhost (which has a similar security issue) because it causes problems when binding to the "any" address on Linux.
Second, once cupsd starts it will create the localhost (or "any" address) listener for you, and stay running indefinitely. And cupsd uses a KeepAlive file to tell systemd to start it up on bootup once you enable the web interface, so it should be running right away unless you've added something to manually start/stop cupsd.
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In Yakkety (16.10), CUPS behaves as intended upstream, not automatically shutting down when it shares at least one printer or the web interface is active (turned on via "WebInterface Yes" in cupsd.conf). So there this bug should be fixed.
In earlier Ubuntu versions, like Xenial (16.04 LTS), there is a patch which allows for CUPS auto shutdown due to another problem, whgich is fixed in later CUPS versions. This fix needs to get backported so that auto shutdown can be suppressed with active web interface, to match the upstream standard.