Newly installed cable modem caused loss of wifi scanner connection

[guy]

I'm trying to help a neighbor, I have basic user level knowledge of
Linux, he doesn't have any.
I installed Linux Mint 17 on his Dell Laptop and successfully installed
his wireless HP Deskjet 3520 Printer/scanner. The scanner has worked
well for about 4 months. The other day his cable provider installed a
new router, I was able using CUPS to install his printer but Simple Scan
and Xsane do not see the scanner. I assumed its do to a change of IP
address. However, I cannot find any facility for checking the IP
configuration setting.

I look forward to any suggestions in resolving this lack of connectivity.

[Roger]

Post by guy
I'm trying to help a neighbor, I have basic user level knowledge of
Linux, he doesn't have any.
I installed Linux Mint 17 on his Dell Laptop and successfully installed
his wireless HP Deskjet 3520 Printer/scanner. The scanner has worked
well for about 4 months. The other day his cable provider installed a
new router, I was able using CUPS to install his printer but Simple Scan
and Xsane do not see the scanner. I assumed its do to a change of IP
address. However, I cannot find any facility for checking the IP
configuration setting.
I look forward to any suggestions in resolving this lack of connectivity.

This is another reason I deplore networked printers, if you change the default
route (or replace the router), you'll need to change the printer's IP settings
prior to instituting the changes with new router settings. Some printers (and
devices) do have a display you can navigate to change the IP address of the
unit.

Some units do not, requiring you to either set the unit's IP settings to either
default (eg. DHCP if you're luck) or you'll need to reconnect to the printer
with either the old router settings or by directly connecting the unit to the
computer. (The later, can be more difficult.)

If the HP printer's IP address is 192.168.1.115 and you switched the default
route from 192.168.1.1 to 192.168.2.1, you'll need to switch the printer's IP
address to 192.168.2.115. (Take note of a change of the second from last
digit, denoting routing.)

Following is a more brief example.

Before:
192.168.1.115
via route 192.168.1.1

After should be:
192.168.2.115
via route 192.168.2.1

[Gene Heskett]

Post by Roger

Post by guy
I'm trying to help a neighbor, I have basic user level knowledge of
Linux, he doesn't have any.
I installed Linux Mint 17 on his Dell Laptop and successfully
installed his wireless HP Deskjet 3520 Printer/scanner. The scanner
has worked well for about 4 months. The other day his cable
provider installed a new router, I was able using CUPS to install
his printer but Simple Scan and Xsane do not see the scanner. I
assumed its do to a change of IP address. However, I cannot find
any facility for checking the IP configuration setting.
I look forward to any suggestions in resolving this lack of
connectivity.

This is another reason I deplore networked printers, if you change the
default route (or replace the router), you'll need to change the
printer's IP settings prior to instituting the changes with new router
settings. Some printers (and devices) do have a display you can
navigate to change the IP address of the unit.
Some units do not, requiring you to either set the unit's IP settings
to either default (eg. DHCP if you're luck) or you'll need to
reconnect to the printer with either the old router settings or by
directly connecting the unit to the computer. (The later, can be more
difficult.)
If the HP printer's IP address is 192.168.1.115 and you switched the
default route from 192.168.1.1 to 192.168.2.1, you'll need to switch
the printer's IP address to 192.168.2.115. (Take note of a change of
the second from last digit, denoting routing.)
Following is a more brief example.
192.168.1.115
via route 192.168.1.1
192.168.2.115
via route 192.168.2.1

And even better idea is to setup ones home network at 182.168.XX.ZZ.

Most important thing you can do is buy a router with enough flash memory
so it can be reflashed with dd-wrt.

dd-wrt has been installed here for many years, on several different
routers. I use /etc/hosts as the local dns lookup, and if that fails its
handed off to the router. In over a decade, only one person has accessed
this network and its machines, a friend I needed help from, and I had to
give him the password. I have a brother printer with LAN access, and I
can change its address from its own control panel, so its set in the
same XX block, and two entries in the /etc/hosts file, one for its
scanner, and a duplicate for the printer as its an MFC machine.

The web page in the sig is NAT'ed to this machine by the router, and nmap
can't find any leaks in the sandbox I run apache2 in, but you can browse
freely and download anything that interests you.

I don't run a firewall on any of these currently 7 machines, dd-wrt is my
guard dog. These decent routers all have radios in them, but they cannot
access my network thru the radio, only steal some of my bandwidth to the
internet. And I only turn the radio on when one of my boys visits with
one of these fawncy cell phones that needs a wifi.

Having control over who comes in, is a nice secure feeling, and you can't
have that feeling with any router out of the box as all have NSA or
similar backdoors. dd-wrt has no back doors you didn't create and know
about.

I have 2 such routers, only one in service at any one time, 1st is a
Buffalo NetFinity, the 2nd for emergency use is a netgear running at the
Buffalo's MAC address by cloning, that so my internet address isn't
changed by my ISP when I use the netgear. It's also reflashed with
dd-wrt. But I've found the netgear is forgetfull, and needs a powerdown
reboot about weekly to restore everything.

An old farts 2 cents. Adjust for inflation since 1934.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

[Roger]

Roger,
Thanks for your reply. If I understand your comment I need to change
routing in the Sane application. If I'm correct is the following file
where I make this change: /etc/sane.d/net.conf?
Guy

You'll probably first need to go through and verify all network settings are
set to the appropriate routing number, while also paying attention to the digit
I advised you previously within the device's IP address. If settings are set
to DHCP, you can likely safely disregard this IP/routing change, and if
possible, just verify the device has acquired a good IP/routing numbers.

Then of course, verify any firewalls enabled are not interferring by
temporarily disabling the firewall.

Lastly, check the Sane IP/routing settings.

[Roger]

Roger,
Please bear with my confusion.
Since the installation of the new cable modem, the neighbor's laptop
surfs the Internet, it print over wifi to the remote multi-function
printer within the same internal network, 192.168.1.x.
The only thing not working is sane, it doesn't see the multi-function
printer/scanner.
What would be the reason to do anything other than ensuring sane has the
correct IP of the scanner?
Guy

You mentioned it's an HP printer/scanner, make sure you have the hpaio driver
installed and that "hpaio" is listed within the /etc/sane.d/dll.conf file.

[Yury Tarasievich]

Knowing the linux ways, you'll have to fiddle in
the network configuration part.
Basicly, the wifi configuration is doable in
three steps (all from command line):

ifconfig wlan0 up
iwconfig wlan0 essid 'name_of_your_wifi_network'
dhclient wlan0

In modern and oh-so-helpful distros, once you've
went throught the motions of installing the
system, the tools for CHANGING the network setup
(say, wifi access parameters) stay virtually
hidden away under the layers of GUI tools.

Post by guy
I'm trying to help a neighbor, I have basic user

...

[guy]

-------- Forwarded Message --------
Subject: Re: [sane-devel] Newly installed cable modem caused loss of
wifi scanner connection
Date: Thu, 30 Mar 2017 21:01:46 -0400
From: guy <***@gmail.com>
To: Roger <***@gmail.com>



Will do, thanks for the follow-up

Post by Roger

Roger,
Please bear with my confusion.
Since the installation of the new cable modem, the neighbor's laptop
surfs the Internet, it print over wifi to the remote multi-function
printer within the same internal network, 192.168.1.x.
The only thing not working is sane, it doesn't see the multi-function
printer/scanner.
What would be the reason to do anything other than ensuring sane has the
correct IP of the scanner?
Guy

You mentioned it's an HP printer/scanner, make sure you have the hpaio driver
installed and that "hpaio" is listed within the /etc/sane.d/dll.conf file.