On 30/01/2008, alan c <aeclist@???> wrote:
> I am having trouble understanding how to temporarily use my edimax
> printsir PS-901 print server unit in an friends PC and network.
>
> My unit is physically small, hardly big enough to have the parallel
> socket on one end - and it works fine on my network. I originally set
> it years ago to use IP address 192.168.1.25 (presumably by following
> instructions key by key.....), and this IP works ok too. I have had it
> for some time, and since I have never needed to mess with it, I have
> never expanded my very limited understanding of the issues relating to
> it, and the network.
>
> My home network has a vigor wired adsl modem 4 port router and I run
> utp cabes from this variously round the house and in several places
> have switches to fan out to other PCs and printers. All the switches
> are basic self managed auto units. Most kit is not often on all
> together, usually only one or two at a time. This is mostly a hobby
> network.
>
> My router is 192.168.1.1 and has dhcp on. I can put a PC on any place
> in the house and set up to print direct (TCP I think) to the print
> server address with its printer. It all works very well.
>
> On my network, if I use a browser addressed to 192.168.1.25 I start
> talking to the print server web page, no problem.
>
> 1) I took the unit to my friend's office and plugged the unit onto a
> printer, ethernet cabled it up to an ethernet switch that several PCs
> were also connected to, and found that PC/s did not communicate
> successfully with the print server. The office network modem router is
> 192.168.2.1. I suspect my lack of appreciation of subnetworks is a
> problem here, but what exactly?
>
> 2) I looked at some printserver instructions for somewhat similar
> units and then tried: took a PC, disconnected its ethernet cable,
> connected it straight to the printserver (by itself, no printer),
> changed the PC fixed IP from its original 192.168.2.104 to various
> other numbers. But did not seem to be able to communicate with the
> unit. The handbooks talk about an initial (post factory) setup needing
> PC as 10.0.0.2 and print server address will respond as 10.0.0.1, get
> its http pages and then change its IP address from 10.0.0.1 to
> something else. I did not even get as far as gettin through to it, any
> method.
>
> A ping to 192.168.1.25 did not get through, for example. I do not
> understand why, because the unit thinks it is that IP.
> All Pcs I used were ubuntu or kubuntu
>
> I conclude that there are a few basics I am missing with basic IP
> stiff and subnets?
>
> Given that the unit's IP is 192.168.1.25 and I can change a PC's IP to
> anything I want on a non crossed UTP ethernet cable directly between
> them, what am I missing please? Was I getting close? (crossed cable
> needed??)
>
> tia
> --
> alan cocks
> Kubuntu user#10391
>
Your suspicions are correct. This is a IP subnets issue.
You would do very well to google for some good guides to how IP
networking works before trying to plug something into someone else's
network.
About the simplest explanation I can give regarding IP subnets is this.
Think of the numbers as binary numbers.
e.g.
255.255.255.255 is 11111111.11111111.11111111.11111111
255.255.255.0 is 11111111.11111111.11111111.00000000
For networking, the IP address is split into two parts. The "network"
part and the "host" part.
The way to split an IP address into two parts is by using the subnet mask.
So, if you have an IP address of 192.168.1.25 and a subnet mask of
255.255.255.0, you get (in binary):
IP address: 11000000.10101000.00000001.00011001
Subnet Mask: 11111111.11111111.11111111.00000000
network part: 11000000.10101000.00000001.00000000 or 192.168.1.0
host part: 00000000.00000000.00000000.00011001 or 0.0.0.25
Notice how the separation works at the point where the subnet mask
changes from 1s to 0s.
Now, only those hosts (in your case a PC or print server) with the
same "network" part can communicate. I.e. pings will work.
If the "network" part or subnets are different the hosts cannot talk
to each other and instead rely on a piece of equipment with "routing"
functionality. A router would have two or more IP addresses on on each
IP subnet and therefore be able to "route" IP packets between the two
subnets.
So, from your problem:
192.168.1.25 is on subnet 192.168.1.0
192.168.2.104 is on subnet 192.168.2.0
(assuming a subnet mask of 255.255.255.0)
so they cannot talk to each other unless a router helps.
So to talk to 192.168.2.104, you need to have an IP address of
192.168.2.something. 192.168.1.something will not work for reasons
explained above.
To find out the current subnet mask, in linux go to a terminal windows and do
/sbin/ifconfig
You will get something like this:
eth0 Link encap:Ethernet HWaddr 00:0D:9D:91:74:15
inet addr:192.168.1.101 Bcast:192.168.1.255 Mask:255.255.255.0
....
The subnet mask is written as "Mask:255.255.255.0" above.
James
