Linux box (ex-router) causing duplicates on Windows/Linux ..

Hi,

Small LAN setup at home. Big problem. I have three Linux boxes and a
Windows XP box running Winroute connected to the 'net, doing NATting
and firewalling me (yeah, it *can* be done with Windoze).

Up until now, I didn't have a hub, so was using a setup similar to
this:


[intif 192.168.100.1] Winbox [extif 213.x] <--> INET
|
|
[eth0 192.168.100.10] Linux1 [eth1 192.168.100.20]
|
|
Linux2 [eth0 192.168.100.11]
|
|
Linux3 [eth0 192.168.100.12]

In this scenario, Linux2 and Linux3 were setup to route via Linux1, no
iptables/chains involved, just ip forwarding. Linux1 had a
well-config'd routing table so as to send packets in the right
directions, and Winbox took care of Internet connectivity, port
forwarding to Linux3 (mail/newsserver) etc.

Now I've got a mega 100Mbps UTP hub, and I thought, hey, I don't want
all that messy cabling, lets just plug everything in together. I
removed eth1 from my 'bridge' (Linux1) and I set the routing tables on
Linux1, 2 & 3 the same:

$ ip route

192.168.100.0/24 dev eth0 scope link
127.0.0.0/8 dev lo scope link
default via 192.168.100.1 dev eth0

so I know the default gateway is config'd ok. When I bring up Linux2
and/or Linux3 -- no problems, everyone 'sees' each other, and I've got
full connectivity between Linux boxen, the Windoze box can see the SMB
shares and the Internet flows thru.

*However* Linux1 (ex 'bridge') seems to be stuck in its ways. It comes
up ok, lets me talk to the other Linux boxes, and (for a while) to the
Windows box, then all networking dies. If I do an 'ifconfig eth0 down'
on Linux1 everything's ok again, so I've isolated it to this box. The
routing table and default gateway is _identical_, promiscuous mode is
definitely OFF, and tcpdump/ping has told me that I'm producing
duplicate packets when PINGing Linux1--->Winbox. I'm going over the
config on Linux1, but TBQH I don't understand why, if the routing
table/default gw is identical, it should be creating all these
problems on its own, _except_ that it's 'history' is as a simple
router, somewhere, something is on that shouldn't be. Anyone got any
pointers, things to check? I'd appreciate *any* input... I could post
tcpdump logs, but they'd only confirm what I've established [bandwidth
save mode=on].

TIA.

Regards,

Jamin

ghost RemoveThis @ntlworld.com (Jamin) wrote in message news:<18924a90.0401252213.1ab65d3b RemoveThis @posting.google.com>...

I have since found out that putting the network card on the Windows
box in promiscuous mode cures the problem, not exactly a solution; and
my Windows knowledge on how to do this is limited to starting a packet
sniffer... the network driver for SMC cards doesn't have a setting --
however this could be indicative of the *cause*. Windows problem ~
windows solution, tho' I still think it lies on the Linux box.

Regards,

Jamin