[PLUG] Network Printer Debugging

[Richard C. Steffens]

Jason Martin wrote:

> On 5/25/07, Richard C. Steffens <rsteff at comcast.net> wrote:
>> I started this morning with the good old fashioned technique of
>> disconnecting all the cables, and then putting them back one at a time
>> until the problem showed up again.
>>
>> First, I tried a crossover cable between my laptop (WinXP) and the
>> printer (Brother MFC7820N). Didn't work.
> 
> This would only work if you had compatible static IP addresses
> configured on both the printer and the laptop.  If either is using
> DHCP it would not work.
>
>> Then I tried just the laptop, the router (disconnected from the cable
>> modem), and the printer. That works.
> 
> If your setup is the standard setup, then the router is your DHCP
> server, so is required.

That explains it. The printer has a static IP address, but the laptop
gets one from the router.

>> When I added the link to the basement, the problem returned. In the
>> basement I have a switch connected to a Thinkpad 390 (Win98SE) and my
>> newly installed Slackware 11 machine. I disconnected the Slackware
>> machine and tried again. The problem went away. At least the problem
>> changed. I need to try again with only the printer, router, and laptop
>> and watch the LCD on the printer to be sure. But, at least printing
>> works again with the Slackware machine out of the picture. Getting real
>> work done has the priority at the moment, so I'll put off watching the
>> traffic with Ethereal, or maybe wireshark, until tomorrow.
> 
> Check the network configuration on the Slackware machine and see if
> you have an address conflict with one of your other devices.  You
> shouldn't need Wireshark/Ethereal to do that.

The Slackware machine is 192.168.0.254; the printer is 192.168.0.252. I
just shut down the Slackware machine, so I'll confirm that tomorrow, or
whenever I get time to play with it some more. I know that I used putty
from the laptop to connect to the Slack ware machine by IP address this
morning, so I'm pretty sure that's correct. I don't know if there are
any other IP addresses lurking about on that machine. I wouldn't think
there would be, but I'll check it out later.

Thanks for your help.

-- 
Regards,

Dick Steffens