Simple hub between DSL modem and netgear router - No link

I want to put a hub between my netgear FM114P router and the crappy
Yamaha DSL modem, so that I can plug a linux box to the hub and gather
traffic info in promisc mode.
I've tried every single combination of physical port on the hub with
crossover and straight through cables. When I connect the netgear router
into the hub, the link light always blinks (instead of remain solid). I
the Internet port on the netgear is an auto-sense port, in the sense
that I can use a straight through cable and it will adjust accordingly.
But, no matter which cable I use, no Link is ever achieved. Connection
between DSL modem, ironically enough, seems to work *regardless* of
which cable I use.
Am I just not giving the netgear router enough time to adjust to the
cable? It has no problem adjusting when I plug the Modem straight to the
router.

Any help appreciated.
jeff

On Fri, 09 Apr 2004 23:07:21 GMT, jeff <(E-Mail Removed)> wrote:
> I want to put a hub between my netgear FM114P router and the crappy
> Yamaha DSL modem, so that I can plug a linux box to the hub and gather
> traffic info in promisc mode.
> I've tried every single combination of physical port on the hub with
> crossover and straight through cables. When I connect the netgear router
> into the hub, the link light always blinks (instead of remain solid). I
> the Internet port on the netgear is an auto-sense port, in the sense
> that I can use a straight through cable and it will adjust accordingly.
> But, no matter which cable I use, no Link is ever achieved. Connection
> between DSL modem, ironically enough, seems to work *regardless* of
> which cable I use.
> Am I just not giving the netgear router enough time to adjust to the
> cable? It has no problem adjusting when I plug the Modem straight to the
> router.

The communication between router and dsl modem is likely PPPoE, which does
not even use any ethernet IPs. So if you are listening for tcp/ip
ethernet traffic on a hub between them, there is none. The tcp/ip to the
internet is encapsulated in the PPP.

--
David Efflandt - All spam ignored http://www.de-srv.com/

David Efflandt wrote:
>
> The communication between router and dsl modem is likely PPPoE, which does
> not even use any ethernet IPs. So if you are listening for tcp/ip
> ethernet traffic on a hub between them, there is none. The tcp/ip to the
> internet is encapsulated in the PPP.
>

Interesting you mention that. I finally managed to get a link between
the router and the hub using straight through, then a crossover between
hub and dsl modem. Internet seems to work as usual. But, once I start up
ethereal, snort, tcpdump, etc., you're right, I don't see any traffic,
which i thought was strange. Ive had problems with this pcmcia card
before, so im recompiling the kernel w/ modules fresh, just to make sure.
Anyway, I've seen multiple references to people putting a hub in front
of their router for a similar purpose as mine. My connection to verizon
is dhcp, so unless the router and modem need to do encapsulation for
their communication purposes, its not applicable here.
Thanks for the reply.

jeff

In article <iiJdc.18780$(E-Mail Removed)>, jeff wrote:

> Interesting you mention that. I finally managed to get a link between
> the router and the hub using straight through, then a crossover between
> hub and dsl modem. Internet seems to work as usual. But, once I start up
> ethereal, snort, tcpdump, etc., you're right, I don't see any traffic,

Are you _sure_ it's a hub and not a switch?

Hubs are very rare these days.

Unless you've got something at least 5 years old that doesn't
support dual speeds (10/100), it's probably a switch. Switches
don't send all packets out all ports, so your sniffer won't see
traffic not destined for it.

--
Grant Edwards grante Yow! I just bought
at FLATBUSH from MICKEY
visi.com MANTLE!

jeff wrote in news:J0Gdc.20570$(E-Mail Removed):

> I want to put a hub between my netgear FM114P router and the
> crappy Yamaha DSL modem, so that I can plug a linux box to the hub
> and gather traffic info in promisc mode.
> I've tried every single combination of physical port on the hub
> with crossover and straight through cables. When I connect the
> netgear router into the hub, the link light always blinks (instead
> of remain solid). I the Internet port on the netgear is an
> auto-sense port, in the sense that I can use a straight through
> cable and it will adjust accordingly. But, no matter which cable I
> use, no Link is ever achieved. Connection between DSL modem,
> ironically enough, seems to work *regardless* of which cable I
> use.
>

hi jeff,
One way that you can do this is showin in an article that you can find
at the following link.

Linux Journal, Peering over the firewall, 23 July 2003
Http://www.linuxjouranl.com/print.php?sid=6985
I think that is the printable version. But it show exactly how to
modify a cable for use with a snort box and hub on a LAN for sniffing.
HtH
--
Cheers,
Kurt

Kurt wrote in news:Xns94C732315396AdisorgFoo@127.0.0.1:

> Http://www.linuxjouranl.com/print.php?sid=6985

Http://www.linuxjournal.com/article.php?sid=6985
sorry for the typo.

--
Cheers,
Kurt

Grant Edwards wrote:
> In article <iiJdc.18780$(E-Mail Removed)>, jeff wrote:
>
> Are you _sure_ it's a hub and not a switch?
>
> Hubs are very rare these days.
>
> Unless you've got something at least 5 years old that doesn't
> support dual speeds (10/100), it's probably a switch. Switches
> don't send all packets out all ports, so your sniffer won't see
> traffic not destined for it.
>

I've had this for a few years. It's labeled "10/100 EZ Hub". Before I
got my netgear router, I was using a linux box with an iptables firewall
and could easily watch all packets on the network using this hub.
Still can't see traffic on it..so, back to square one.

jeff

Kurt wrote:

> Kurt wrote in news:Xns94C732315396AdisorgFoo@127.0.0.1:
>
>
>>Http://www.linuxjouranl.com/print.php?sid=6985
>
>
> Http://www.linuxjournal.com/article.php?sid=6985
> sorry for the typo.
>

Thanks for the link. I'll give it a try over the weekend.

jeff

Grant Edwards wrote:
> In article <iiJdc.18780$(E-Mail Removed)>, jeff wrote:
>
>
>
> Are you _sure_ it's a hub and not a switch?
>
> Hubs are very rare these days.
>
> Unless you've got something at least 5 years old that doesn't
> support dual speeds (10/100), it's probably a switch. Switches
> don't send all packets out all ports, so your sniffer won't see
> traffic not destined for it.
>

Forgot to mention that I can successfully bring up the interface and get
an IP from my isp..so, I'm more than a little confused as to why I can't
see regular traffic.

Kurt <(E-Mail Removed)> wrote in message news:<Xns94C732315396AdisorgFoo@127.0.0.1>...
> jeff wrote in news:J0Gdc.20570$(E-Mail Removed):
>
> > I want to put a hub between my netgear FM114P router and the
> > crappy Yamaha DSL modem, so that I can plug a linux box to the hub
> > and gather traffic info in promisc mode.
> > I've tried every single combination of physical port on the hub
> > with crossover and straight through cables. When I connect the
> > netgear router into the hub, the link light always blinks (instead
> > of remain solid). I the Internet port on the netgear is an
> > auto-sense port, in the sense that I can use a straight through
> > cable and it will adjust accordingly. But, no matter which cable I
> > use, no Link is ever achieved. Connection between DSL modem,
> > ironically enough, seems to work *regardless* of which cable I
> > use.
> >
>
> hi jeff,
> One way that you can do this is showin in an article that you can find
> at the following link.
>
> Linux Journal, Peering over the firewall, 23 July 2003
> Http://www.linuxjouranl.com/print.php?sid=6985
> I think that is the printable version. But it show exactly how to
> modify a cable for use with a snort box and hub on a LAN for sniffing.
> HtH

Since you got your dhcp link to Verizon working OK ... you did, didn't
you? If not yet you might look at this Linux-Verizon fix:
http://groups.google.com/groups?q=g:...ing.google.com

Just in case, that's :
http://www.linuxjournal.com/print.php?sid=6985

Pretty good, basic coverage. Should work for you.

Note that PPPoE client on Linux is not likely needed with most dsl
modems today as they include the client in the modem. Not sure of
yours however.

FYI, Ethereal supports _20_ PPP protocols, including PPPoES (session).
Even tcpdump might capture the packets for you:
tcpdump ether proto 0x8863 '||' ether proto 0x8864

And note that the wire protocol running on an ethernet card _will_ be
ethernet frames -- couldn't be anything else.

hth,
prg
email above disabled