Multiple IP addresses on one line

M

Metspitzer

I was looking at one of these:
http://www.google.com/imgres?imgurl...UdfsIINQdaYLM:;c1hRnoR56X5OwM;BUdfsIINQdaYLM:
It would sit on/next to the TV. I already have one of these on the
den TV and connected to the network:
http://store.digitalriver.com/store...eID=wdus&productID=237609800&themeID=30153100

I was thinking it sure would be nice if the Slingbox or the WDTV had
an extra Ethernet port.

My bedroom TV does have Ethernet port, but I don't use it. I do have
a WDTV at the bedroom TV connected to the network.

I can see a time in the near future where it is going to be everything
with a power cord is going to need an Ethernet port. It seems like
it's time to plan for this. I don't see much more cost in adding two
Ethernet ports to devices so you could just keep daisy chaining things
together. I know that would cause each device to share the bandwidth,
but anytime that would be a problem you could always add another line.

It would seem that the only catch is how IP ports get assigned.
192.168.1.130:1 192.168.1.130:2
 
P

Paul

Metspitzer said:
I was looking at one of these:
http://www.google.com/imgres?imgurl...UdfsIINQdaYLM:;c1hRnoR56X5OwM;BUdfsIINQdaYLM:
It would sit on/next to the TV. I already have one of these on the
den TV and connected to the network:
http://store.digitalriver.com/store...eID=wdus&productID=237609800&themeID=30153100

I was thinking it sure would be nice if the Slingbox or the WDTV had
an extra Ethernet port.

My bedroom TV does have Ethernet port, but I don't use it. I do have
a WDTV at the bedroom TV connected to the network.

I can see a time in the near future where it is going to be everything
with a power cord is going to need an Ethernet port. It seems like
it's time to plan for this. I don't see much more cost in adding two
Ethernet ports to devices so you could just keep daisy chaining things
together. I know that would cause each device to share the bandwidth,
but anytime that would be a problem you could always add another line.

It would seem that the only catch is how IP ports get assigned.
192.168.1.130:1 192.168.1.130:2
Click to expand...

192.168.x.x is a NAT address. It's on the LAN side of your
router, and is un-routable. If I'm sitting here right now,
and I type 192.168.1.130, I don't see *your* computer. We're
insulated from one another. These are "private" addresses,
only visible on the home subnet. So you're not going to
run out of those. But that's in n IPV4 world (and the four
parts to the address, tell you I'm addressing an
IPV4 world 192.168.x.x).

Some day, IPV6 will prevail (much wider addresses), and then
there will be plenty of addresses. You won't necessarily see
NAT in the picture then, and every device could be addressed
from the Internet. By using routers and firewalls, there will be
ways to stop that, so local IPV6 addresses are protected
from the Internet.

NAT was intended as a workaround (for the shortage of
addresses in IPV4, but it's a sort of
"default firewall" right now. The reason OSes have
their own internal software firewall, is planning for
a day and an environment, where there is no long
a private LAN to be expected (one protected by NAT
at the router).

I don't understand your "192.168.1.130:1", and I must have
missed that in my random readings on TCP/IP. It implies
some kind of sub-address.

Paul
 
M

Metspitzer

192.168.x.x is a NAT address. It's on the LAN side of your
router, and is un-routable. If I'm sitting here right now,
and I type 192.168.1.130, I don't see *your* computer. We're
insulated from one another. These are "private" addresses,
only visible on the home subnet. So you're not going to
run out of those. But that's in n IPV4 world (and the four
parts to the address, tell you I'm addressing an
IPV4 world 192.168.x.x).

Some day, IPV6 will prevail (much wider addresses), and then
there will be plenty of addresses. You won't necessarily see
NAT in the picture then, and every device could be addressed
from the Internet. By using routers and firewalls, there will be
ways to stop that, so local IPV6 addresses are protected
from the Internet.

NAT was intended as a workaround (for the shortage of
addresses in IPV4, but it's a sort of
"default firewall" right now. The reason OSes have
their own internal software firewall, is planning for
a day and an environment, where there is no long
a private LAN to be expected (one protected by NAT
at the router).

I don't understand your "192.168.1.130:1", and I must have
missed that in my random readings on TCP/IP. It implies
some kind of sub-address.

Paul
Click to expand...

I was just asking what you would have to happen if devices did come
with two Ethernet ports that could be used to daisy chain devices?
What kind of address could they have to allow two (or more) devices on
one CAT 5 feed? The 192.168.1.130:1 was just my way of asking if
devices could work as a daisy chain?

Also I incorrectly called it an IP address. I was thinking NAT
address.
 
P

Paul

Metspitzer said:
I was just asking what you would have to happen if devices did come
with two Ethernet ports that could be used to daisy chain devices?
What kind of address could they have to allow two (or more) devices on
one CAT 5 feed? The 192.168.1.130:1 was just my way of asking if
devices could work as a daisy chain?

Also I incorrectly called it an IP address. I was thinking NAT
address.
Click to expand...

They're all IP addresses, for Internet Protocol.

We could do this, and no network translation is implied here. All
the addresses are routable. I can see your machine, at metspitzer.com
and you can see mine at paul.com (or some bogus domain we registered):

Metspitzer ---- home ----- teh Internets ----- home ---- Paul
203.17.26.44 router router 123.77.66.55

If we turn on NAT on the routers, the LAN side can be made private,
and the router converts 192.168.1.3 to 203.17.26.44. And on
my side, converts internal 192.168.23.44 to 123.7.66.55. How this
saves addresses, is the addresses on the home LAN (192.168.xx)
cannot be seen from the Internet. As far as the Internet
is concerned, there is just one device at 203.17.26.44 (and
that's your router). You can ping the modem/router box. But you
cannot ping any of Metspitzer's vast collection of Ethernet PCs.

203.17.26.44 123.77.66.55
Metspitzer ---- home ----- teh Internets ----- home ---- Paul
192.168.1.3 router router 192.168.23.44
NAT NAT

As far as I know, NAT won't be necessary in an IPV6 world, so we
could go back to the previous scheme. But there are probably
lots of reasons, for not doing that, and for implementing something
that firewalls off the Internet from the living room TV set.
We don't particularly want that (me pinging your TV set).
NAT, originally intended as an address conservation scheme,
also happens to make a handy stateful firewall. And we may still
want firewalls and barriers, to keep the "hordes" out. (Like
that idiot who hacked some person's wireless baby monitor IP camera,
and tried to wake the child by talking through the speaker
on the thing.)

In addition to pure IPV4, pure IPV6, there are also
schemes for mixing them. Your OS may have a copy of
"6to4" for example, which is a means of working between
the two worlds. If you take a look at the occasional computer
you put together, with some other OS on it, you may notice
some of these bits and pieces that were added to prepare
the computer for IPV6.

My few experiments here with IPV6, I find it too "chatty".
I use the LED indicators on the LAN interfaces here, as
an indication of "shady activity". If I'm not doing anything,
the browsers are shut down, my LAN is quiet enough, I hardly
ever see LEDs flashing. But it's possible to turn on all
sorts of stuff, to the point the LED is quite busy. And then
you can no longer rely on the LED as an indication that
"somebody is knocking at my door".

Where I sit here, if I'm getting scanned too often, I drop
the IP address, and get a new lease over ADSL. If I find an address
where the LEDs on my network boxes aren't flashing, then I'm good
for a while.

Paul
 
Y

Yousuf Khan

192.168.x.x is a NAT address. It's on the LAN side of your
router, and is un-routable. If I'm sitting here right now,
and I type 192.168.1.130, I don't see *your* computer. We're
insulated from one another. These are "private" addresses,
only visible on the home subnet. So you're not going to
run out of those. But that's in n IPV4 world (and the four
parts to the address, tell you I'm addressing an
IPV4 world 192.168.x.x).

Some day, IPV6 will prevail (much wider addresses), and then
there will be plenty of addresses. You won't necessarily see
NAT in the picture then, and every device could be addressed
from the Internet. By using routers and firewalls, there will be
ways to stop that, so local IPV6 addresses are protected
from the Internet.
Click to expand...

There will still be a sort of NAT with IPV6. With IPV6, a device's MAC
address will form it's automatically assigned private address. You won't
need DHCP or DNS to get an automatic private address, as it will be
formed directly from the MAC address. These addresses will be unroutable
though, so you will only be able to use them within a private LAN, just
like NAT addresses in IPV4. In IPV6, private addresses are called Unique
Local Addressing (ULA). All IPV6 private addresses will start with the
hexadecimal number 0xfd... (fdxx:xxxx:xxxx).

In IPV4, the reason you need to the specially assigned NAT addresses and
you need things like DHCP to assign them is because the IP addresses
(32-bit) are smaller than the MAC addresses (48-bit), so you can't form
an IP address based on the MAC address. But in IPV6, the MAC addresses
are much smaller than the IP addresses (128-bit), so MAC addresses can
become a subset of the IP addresses.

http://www.networkworld.com/community/blog/ipv6-addressing-subnets-private-addresses
NAT was intended as a workaround (for the shortage of
addresses in IPV4, but it's a sort of
"default firewall" right now. The reason OSes have
their own internal software firewall, is planning for
a day and an environment, where there is no long
a private LAN to be expected (one protected by NAT
at the router).
Click to expand...

Actually routable IPV6 addresses will still need to be assigned by DHCP
and DNS servers. ULA addresses may be automatic, but they are
unroutable, so routable addresses will need to be assigned through
formal negotiated procedures. The routable addresses will not have
anything to do with the MAC addresses, so devices will potentially have
two IPV6 addresses on the same interface, an assigned one, and an
automatic ULA one. But it's likely that people in a large organization
will not bother to obtain assigned addresses for every little device
that works on their network, and obtain only a few addresses for their
routers which will then redirect traffic between the LAN and the WAN.
I don't understand your "192.168.1.130:1", and I must have
missed that in my random readings on TCP/IP. It implies
some kind of sub-address.
Click to expand...

Yeah, the x.x.x.x:y where the x represents the IPv4 address, and y
represent a port number.

Yousuf Khan
 
Y

Yousuf Khan

I was just asking what you would have to happen if devices did come
with two Ethernet ports that could be used to daisy chain devices?
What kind of address could they have to allow two (or more) devices on
one CAT 5 feed? The 192.168.1.130:1 was just my way of asking if
devices could work as a daisy chain?
Click to expand...

Why would you need that? Ethernet was originally a bus architecture,
meaning multiple devices shared the same piece of wire between them.
Yes, it resulted in data collisions between the devices if they didn't
get their timings right, but there were mechanisms for handling that too.

Eventually modern Ethernet evolved into a star architecture, with a
central hub (actually a switch) managing all of the traffic from various
devices, and each device was given its own unique piece of wire to the
hub, not shared with any other device. However, when push comes to
shove, you can still make devices share the same physical wire, even if
they have separate IP addresses. The mechanism for managing collisions
in Ethernet still exist, so that means the mechanism for sharing the
wire still exists.
Also I incorrectly called it an IP address. I was thinking NAT
address.
Click to expand...

A NAT address is also an IP address, just a private one, that's all.

Yousuf Khan
 
P

Paul

Yousuf said:
There will still be a sort of NAT with IPV6. With IPV6, a device's MAC
address will form it's automatically assigned private address. You won't
need DHCP or DNS to get an automatic private address, as it will be
formed directly from the MAC address. These addresses will be unroutable
though, so you will only be able to use them within a private LAN, just
like NAT addresses in IPV4. In IPV6, private addresses are called Unique
Local Addressing (ULA). All IPV6 private addresses will start with the
hexadecimal number 0xfd... (fdxx:xxxx:xxxx).

In IPV4, the reason you need to the specially assigned NAT addresses and
you need things like DHCP to assign them is because the IP addresses
(32-bit) are smaller than the MAC addresses (48-bit), so you can't form
an IP address based on the MAC address. But in IPV6, the MAC addresses
are much smaller than the IP addresses (128-bit), so MAC addresses can
become a subset of the IP addresses.

http://www.networkworld.com/community/blog/ipv6-addressing-subnets-private-addresses



Actually routable IPV6 addresses will still need to be assigned by DHCP
and DNS servers. ULA addresses may be automatic, but they are
unroutable, so routable addresses will need to be assigned through
formal negotiated procedures. The routable addresses will not have
anything to do with the MAC addresses, so devices will potentially have
two IPV6 addresses on the same interface, an assigned one, and an
automatic ULA one. But it's likely that people in a large organization
will not bother to obtain assigned addresses for every little device
that works on their network, and obtain only a few addresses for their
routers which will then redirect traffic between the LAN and the WAN.


Yeah, the x.x.x.x:y where the x represents the IPv4 address, and y
represent a port number.

Yousuf Khan
Click to expand...

Maybe I would have tweaked to the port number, if it was one
of the higher ones than "1" :) Like maybe 192.168.1.130:80
or even 192.168.1.130:8080 would have gotten my attention.
The lowest value that is also popular is probably :21 for FTP.

http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

The usage of :1 and :2 implied enumeration, and perhaps that's
why I didn't recognize it as such.

As for the IPV6, I thought there was a push on a while back,
to get it deployed, but I haven't seen anything from my ISP.
I still don't seem to be forced to use it.

Paul
 
Y

Yousuf Khan

Maybe I would have tweaked to the port number, if it was one
of the higher ones than "1" :) Like maybe 192.168.1.130:80
or even 192.168.1.130:8080 would have gotten my attention.
The lowest value that is also popular is probably :21 for FTP.

http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

The usage of :1 and :2 implied enumeration, and perhaps that's
why I didn't recognize it as such.
Click to expand...

Yup, and let's not forget Port 7, the Echo protocol, isn't that what's
used to ping servers?
As for the IPV6, I thought there was a push on a while back,
to get it deployed, but I haven't seen anything from my ISP.
I still don't seem to be forced to use it.
Click to expand...

I don't know how it's going to work. At some point it's going to get
really critical to upgrade. Right now a lot of work is being done by
private nets, even on the server side. So there need to upgrade is not
urgent yet.

Yousuf Khan
 
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