david wrote:
On Tue, 22 Sep 2009 13:16:31 -0400, Smarty rearranged some
electrons to
say:
Smarty wrote:
Smarty wrote:
Thanks to all for replies.
I would very much like to fix the assignments to MAC addresses,
since each of my 8 video clients has a label with the Mac address
printed on it, and all 8 clients remain located in exactly the
same
network locations regardless of when I reboot. The fact that they
are, in most cases, connected to switches fed from the router
causes
additional confusion when the video server IP changes, since the
switches appear to "keep" old routing information for a while and
sometimes require rebooting also.
I have looked over my Linksys settings pretty carefully but
have yet
to find a method to put hard-wired Mac addresses into this
Linksys
router. I may switch to another router if I can be certain
that it
supports this feature and also has the ability to route to a
couple
dozen devices reliably.
Thanks again for the help!
I cannot understand why you want to do anything with the MAC
addresses. As I understand it your 8 video clients are just that
"clients". Your router does not need to know about the clients and
neither does the server. The server PC is the only one that
needs a
fixed IP address so the clients can find it.
As long as the 8 clients are all DHCPing their IP settings
(address,
mask, etc) it doesn't matter WHICH address they get from the DHCP
server. Every address in the DHCP range will work fine for every
client machine.
The rule of thumb is... server = fixed IP, client = DHCP.
Rarius
The issue (apparently) is that loss of power / reboot, using a
dynamic
IP for the video server, can and often does result in a new video
server IP address being assigned when the router / video server
come
up. The 8 clients use BootP to upload a copy of their run-time
(Linux)
application which contains the client GUI, mpeg2 decoder, etc. for
playback. They fail to find the boot server, now at a new
address, and
are (apparently) not able to easily get themselves booted. I am
hoping
that a fixed IP address for the video server, where the 8
clients get
their boot server uploads, will now be much less difficult and time
consuming.
I raised the entire matter of MAC addresses only because each of
the 8
clients has a clearly labeled and unique hard-coded MAC address
which
(if I had a way to create a map / table in my video server) could
route 'instantly' without the ambiguity of issuing new IP addresses
for both the video server and 8 clients every time a power glitch
occurs. It is my impression that 3 100BaseT Netgear switches I
use in
my network also have some "memory" in their port multicasting
logic /
look up table which "remembers" the prior IP addresses of the
clients
attached to them, and thus becomes a temporary dead-end for packets
being routed to the new client IP addresses after DHCP assignments
occur following reboot. Unplugging the switches and plugging
them in a
minute or two later seems to solve this problem, but there is a
temporary period where the switches don't seem to be forwarding
properly during the BootP process. Thus I brought up Mac
addresses as
an alternative way to perhaps avoid the DHCP quagmire.
My apologies if the original post was incomplete, vague, or
both. I am
going to try the recommended approach to fix the video server IP
address statically, now that I understand that the Linksys can
route
to the entire range of addresses in the subnet, beyond the range I
have defined for automatic DHCP assignment. Perhaps this will be
enough of a solution.
Many thanks again.
Hi,
Ahhh... Ok, that's better... thanks for the explanation of what
you're
actually trying to do.
So, are you saying that "your" server (the one for which you were
trying to set a fixed IP address) is also acting as a BOOTP server?
I haven't worked with this kind of stuff for awhile (use to work
with
PXE/TFTP booting, etc., but years ago!), but, according to this:
http://en.wikipedia.org/wiki/Bootstrap_Protocol
"The Dynamic Host Configuration Protocol (DHCP) is a more advanced
protocol for the same purpose and has superseded the use of
BOOTP. Most
DHCP servers also offer BOOTP support."
Do you know whether or not whatever is acting as the DHCP server on
your network (I'm assuming that router) is also acting as a BOOTP
server?
If it is, and if "your" server is also acting as a BOOTP server,
maybe
that's part of your problem?
According to this:
http://www.eventhelix.com/RealtimeMantra/Networking/Bootp.pdf
the client sends a BOOTP_REQUEST using UDP, with a broadcast
(255.255.255.255) destination address.
[NOTE: If the clients are indeed sending the BOOTP_REQUESTs with UDP
and a broadcast address, then setting your server to a fixed IP
address
is probably not what your problem is, since your server should
see the
broadcast request regardless of its own IP address.]
So, if BOTH your router AND "your" server are acting as BOOTP
servers,
maybe both of them are responding to the BOOTP_REQUEST?
It might be worthwhile to run a separate machine on the network,
with a
sniffer (e.g., Wireshark) running, to see what is going on?
Jim
Jim,
I am very interested in your earlier comment about sniffers /
Wireshark,
and wonder if you or others here may be aware of any very low cost or
freeware method to do some network analysis of traffic. I don't
expect
much given my requirement to keep it cheap / low cost, but I would be
curious to see what tool or tools might be good for looking at
traffic,
not necessarily using a dedicated / separate computer as the sniffer.
Any thoughts would be much appreciated.
google --> wireshark
Hi,
As david pointed out, Wireshark is free. I also occasionally use
Nirsoft
SmartSniff:
http://www.nirsoft.net/utils/smsniff.html
which is also free, esp. when I don't want to, or can't install
WinPcap on
a system.
Jim
Thanks to you and David for replies. I previously went to Google and
found a
misleading website offering Wireshark on a trial basis for free, and
then
offering a $499 purchase price. Had I done more investigating, as I did
tonight, I would have realized that Wireshark is what Ethereal is now
renamed, and that it is open source and free. I have used Ethereal a few
years ago, and had forgotten about it as a suitable tool for this
type of
use. I'm going to have to play around with it again and see how it
works.