PDA

View Full Version : SlimServer: multiple PCs behind router



James Psota
2004-09-29, 00:11
Hi All,

I have a SlimServer question...

How can I get my server to talk to multiple devices that are behind
the same router (and thus sharing the same external IP)? I can have
multiple PCs connected behind a router (running NAT) connect to the
same stream, but not distinct streams. Note that both the server and
the client PCs are behind the same router, so, say, the NAT'ed IPs are
as follows:

SlimServer: 192.168.0.15
PC 1: 192.168.0.2
PC 2: 192.168.0.3

However, when I connect to SlimServer, it sees both PCs with the
external IP, as opposed to the NAT'ed IP. If I could just get the
SlimServer to look at the NAT'ed IP instead of the external IP, I
think I would be fine. I believe this should be possible since one can
connect multiple Sqeezeboxes to the same server, and still have them
play distinct streams.

Any thoughts or help would be greatly appreciated.

Thanks,
jim

Roy M. Silvernail
2004-09-29, 03:56
On Wed, 2004-09-29 at 03:11, James Psota wrote:
> Hi All,
>
> I have a SlimServer question...
>
> How can I get my server to talk to multiple devices that are behind
> the same router (and thus sharing the same external IP)? I can have
> multiple PCs connected behind a router (running NAT) connect to the
> same stream, but not distinct streams. Note that both the server and
> the client PCs are behind the same router, so, say, the NAT'ed IPs are
> as follows:
>
> SlimServer: 192.168.0.15
> PC 1: 192.168.0.2
> PC 2: 192.168.0.3

It looks to me like you have a routing problem. If all three machines
are behind the router on the same LAN segment, they should talk to each
other from their LAN addresses as shown. In fact, the whole concept of
NAT is that machines on the NAT'd LAN segment have no knowledge of the
external IP address. All they know is that non-local addresses are
reached through the gateway.

The only time any of these machines will show up as the external IP
adress is when connecting to a non-local address through the router. So
if SlimServer is seeing connections from the external IP address, it can
only be because the connection is coming *from* the router. But because
NAT is only supposed to translate for connections outside the local
segment, the router should never touch intra-LAN connections.

> However, when I connect to SlimServer, it sees both PCs with the
> external IP, as opposed to the NAT'ed IP. If I could just get the
> SlimServer to look at the NAT'ed IP instead of the external IP, I
> think I would be fine. I believe this should be possible since one can
> connect multiple Sqeezeboxes to the same server, and still have them
> play distinct streams.

This suggests that PC1 and PC2 may be misconfigured. I would check the
network config on both machines to make sure that they are properly
receiving unique addresses from DHCP (or are configured to different
192.168.0.x addresses, if you use static addressing) and that they both
have unique MAC addresses. All ethernet cards are supposed to have
unique MACs, but I've seen at least one mention on this list of 2 el
cheapo cards that had the same MAC.
--
Roy M. Silvernail is roy (AT) rant-central (DOT) com, and you're not
"Progress, like reality, is not optional." - R. A. Hettinga
SpamAssassin->procmail->/dev/null->bliss
http://www.rant-central.com

James Psota
2004-09-29, 08:29
Thanks, Roy. This helped me solve the problem -- I had to delete the
old "player" that used the external IP from when I used to access the
server via a dyndns forwarding URL, which clearly went through the
router. After I did this, slimserver recognized the new NAT'ed IPs
correctly.

jim


On Wed, 29 Sep 2004 06:56:14 -0400, Roy M. Silvernail
<roy (AT) rant-central (DOT) com> wrote:
> On Wed, 2004-09-29 at 03:11, James Psota wrote:
> > Hi All,
> >
> > I have a SlimServer question...
> >
> > How can I get my server to talk to multiple devices that are behind
> > the same router (and thus sharing the same external IP)? I can have
> > multiple PCs connected behind a router (running NAT) connect to the
> > same stream, but not distinct streams. Note that both the server and
> > the client PCs are behind the same router, so, say, the NAT'ed IPs are
> > as follows:
> >
> > SlimServer: 192.168.0.15
> > PC 1: 192.168.0.2
> > PC 2: 192.168.0.3
>
> It looks to me like you have a routing problem. If all three machines
> are behind the router on the same LAN segment, they should talk to each
> other from their LAN addresses as shown. In fact, the whole concept of
> NAT is that machines on the NAT'd LAN segment have no knowledge of the
> external IP address. All they know is that non-local addresses are
> reached through the gateway.
>
> The only time any of these machines will show up as the external IP
> adress is when connecting to a non-local address through the router. So
> if SlimServer is seeing connections from the external IP address, it can
> only be because the connection is coming *from* the router. But because
> NAT is only supposed to translate for connections outside the local
> segment, the router should never touch intra-LAN connections.
>
> > However, when I connect to SlimServer, it sees both PCs with the
> > external IP, as opposed to the NAT'ed IP. If I could just get the
> > SlimServer to look at the NAT'ed IP instead of the external IP, I
> > think I would be fine. I believe this should be possible since one can
> > connect multiple Sqeezeboxes to the same server, and still have them
> > play distinct streams.
>
> This suggests that PC1 and PC2 may be misconfigured. I would check the
> network config on both machines to make sure that they are properly
> receiving unique addresses from DHCP (or are configured to different
> 192.168.0.x addresses, if you use static addressing) and that they both
> have unique MAC addresses. All ethernet cards are supposed to have
> unique MACs, but I've seen at least one mention on this list of 2 el
> cheapo cards that had the same MAC.
> --
> Roy M. Silvernail is roy (AT) rant-central (DOT) com, and you're not
> "Progress, like reality, is not optional." - R. A. Hettinga
> SpamAssassin->procmail->/dev/null->bliss
> http://www.rant-central.com
>