Allegedly, on or about 06 May 2017, Javier Perez sent:
Tried with tcdump -n host printer_ip and opened up all the ports I
could see on the dump. Did not work out.
Just being cautious, but did you write the IP of the printer, or did you
actually type in "tcdump -n host printer_ip"?
It ought to be something like: tcdump -n 192.168.1.20
(assuming that was the IP for your printer).
I'm not familiar with tcdump, but at the moment I'm wonder if it only
shows successful traffic?
Ended up accepting all the traffic from the printer IP on the
firewall.
Now it works.
That can come back to byte you (pun intended). If anything comes onto
your network using that same IP, it's allowed through your firewall. If
anything can hack your printer, and that's possible with wireless
enabled devices, your printer can a trojan gateway into your network.
If your printer gets assigned a different IP, one day, printing stops
working.
I recently had to fight may through to getting printing working properly
on Fedora 25 (or was it 24?), in essence I had to set the firewall to
allow ipp client and server (allowing TCP and UDP data on port 631), had
to remember to make those permanent settings. Had to set a CUPS admin
option to show printers shared by other systems, I did that through its
web interface <
http://localhost:631/>. And I can't remember having to
do anything (years ago, I may have also had to set a SELinux option
about printing).
--
[tim@localhost ~]$ uname -rsvp
Linux 3.9.10-100.fc17.x86_64 #1 SMP Sun Jul 14 01:31:27 UTC 2013 x86_64
Boilerplate: All mail to my mailbox is automatically deleted, there is
no point trying to privately email me, I only get to see the messages
posted to the mailing list.
Just because nobody complains, it doesn't mean that all parachutes are
perfect.