[PLUG] Printers and IP addresses

[Mike C.]

>
>
> > The only problem is that the router doesn't see any of the printers,
> >
>
> This is because you have set all the IP addresses for your printers
> manually. The router only tracks IP addresses for devices which have
> requested an IP from it.
>
>
Not exactly true. Any networked ethernet device will have at least a mac
table/arp cache that contains the ip address and mac address of locally
connected devices. The command "arp -a" from the command line will show you
what locally connected ethernet devices a printer, computer, switch or
router knows about.

A switch or a router contains a CAM table which lists the MAC addresses and
what ports they are known on. This is so that when ethernet frames come
into the switch/router, it knows which port to send the packets out in
unicast instead of broadcasting out all the ports like a hub.

Looking at the screenshot in this tutorial, the computer name can be an ip
address, which is very common practice with printers.
http://www.gilsmethod.com/how-to-reserve-ip-addresses-with-d-link-routers

If you don't see the mac or ip address listed then the network might be
segmented in some way. Can you ping the ip addresses of the printers? If
you can then they should be populated into the CAM table and be able to be
selected from the drop down menu.

>
> > even though I turned them all on. Therefore, I can't see an easy way to
> > reserve addresses for them. In each case the printer's IP address was
> > set on its control panel. I suppose I could fumble around in their
> > control panels to see if I could find a way to identify it to the
> > router,
>
> You've already mitigated this by issuing a DHCP reservation for your
> other devices so they won't collide with your static assignments any
> more. However the next time you plug something in, it's only a matter of
> time before this happens again. You should segregate your IP address space
> such that devices configured statically are assigned addresses outside
> your router's DHCP range. You can change either the static IPs or the DHCP
> range (or both) to accomplish this.
>
> -wes
>

Yes, as Wes is saying, set your DHCP pool range to like .100 to .150 and
then just configure static ip addresses outside of that range. You'll just
have to document them or not and just ping what you think is the next
available, non-dhcp range ip address on your network.

Hope this makes some sense...

Cheers,

Mike