Andreas Janssen wrote:

Thanks for your response.

>>>> I have an HP OfficeJet K80 Xi connected to /dev/lp0 of a machine on
>>>> my network which has a firewall. I have opened the ipp port (631) on
>>>> that machine
>>>
>>> TCP and UDP?
>>>
>> TCP
>
> Maybe Cups also needs UDP support. This is at least used for browsing, I
> don't know if it is required if you know the IPs of printer and client.
> But it would be worth a try.

Done. Restarted the firewall.

Restarted the cups server :

cupsd: Child exited with status 98!
cups: restarted scheduler.
root@host:~# lpstat -v
system for hpoj: localhost
system for NetworkPrinter: localhost
system for all: localhost
Printer 'hpoj@localhost' - cannot open connection - No such file or
directory
Make sure the remote host supports the LPD protocol
Printer 'NetworkPrinter@localhost' - cannot open connection - No such file
or directory
Make sure the remote host supports the LPD protocol
Printer 'all@localhost' - cannot open connection - No such file or directory
Make sure the remote host supports the LPD protocol

NetworkPrinter is a printer class that contains hpoj (the printer of
interest).

I get the same error as before.

>
>> [...]
>
>>> Can you telnet to the port on the host?
>>
>> No.
>>
>> §» telnet 192.168.1.1:631
>> telnet: could not resolve 192.168.1.1:631/telnet: Name or service not
>> known
>
> Wrong syntax, try
>
> telnet 192.168.1.1 631

Oops.

§» telnet 192.168.1.1 631
Trying 192.168.1.1...
telnet: Unable to connect to remote host: Connection refused

Thanks.

Andreas Janssen wrote:

Thanks for your response.

>> Done. Restarted the firewall.
>>
>> Restarted the cups server :
>>
>> cupsd: Child exited with status 98!
>> cups: restarted scheduler.
>> root@host:~# lpstat -v
>> system for hpoj: localhost
>> system for NetworkPrinter: localhost
>
> Toyed around with the Listen option, and it looks like it won't work
> unless you add the line for localhost:
>
> Listen 127.0.0.1:631
> Listen 192.168.1.1:631
>
> Try again after you changed that. By the way, take a look at
> netstat -ln -A inet
>
> It should show port 631 opened on the loopback and LAN interfaces.
>
> best regards
> Andreas Janssen
>

I tried what you suggested and I now suspect that the problem lies with my
firewall configuration. I cannot telnet to the host on port 631, even
though I have made an attempt to modify my firewall script
( http://www.eecs.umich.edu/~chhabra/slrcfirewall.txt ).

In particular, I have :

$IPTABLES -A INPUT -p UDP -i $LAN_IFACE -s 0/0 --dport $IPPPORT -j ACCEPT
$IPTABLES -A INPUT -p TCP -i $LAN_IFACE -s 0/0 --dport $IPPPORT -j ACCEPT

where $IPPPORT is 631.

Thanks for the help.