Teksavvy cable modems

[Ansar Mohammed]

Thats pretty much my exact configuration.One additional note, I am
using 801.q VLANs. If you are having issues getting the GS108E to work
ping me offline and I will show you my config. I do have VLAN trunking
enabled.

I tested the VLANs without the router and they appear to be properly
configured.

I guess the fundamental questions here are
1. If I plug my Cable modem and firewall into a hub or switch, will
they work just as if i connected them "back to back". i.e. I am issued
a non RFC 1918 address and I am "on" the internet.
2. If I plug my cable modem onto a network segment with more than one
system that is configured with DHCP how many IP Addresses will
Teksavvy issue to me?

Thanks all for the help so far.




On Fri, Mar 9, 2012 at 2:12 PM, Lennart Sorensen
<lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org> wrote:
> On Fri, Mar 09, 2012 at 12:28:14PM -0500, Ansar Mohammed wrote:
>> I have Teksavvy cable and I have a few questions.
>>
>> Right now the cable modem is connected directly to a dedicated
>> ethernet port on my firewall. My firewall connects to the internal
>> network with a second dedicated ethernet port.
>>
>> Yesterday I setup a dedicated VLAN and plugged both the cable modem
>> and my firewall into it. For some rather odd reason, the external
>> interface of the firewall does not get an IP Address from DHCP. The
>> requests are sent out but no responses come back. I also see tons of
>> arp requests from the cable modem.
>>
>> Any ideas why I am not getting an IP Address?
>
> We need a diagram of the wiring to understand this.
>
> What should work:
>
>  +--------------------------------------------+
>  |                 switch                     |
>  |     vlan1                 +---vlan2---+    |
>  |     |   |                 |   |   |   |    |
>  |    P1   P2                P3  P4  P5  P6   |
>  +----|----|-----------------|---|---|---|----+
>       |    |                 |   |   |   |
> Cable -+    +---Router--------+   |   |   |
>                                  |   |   |
>                                   Clients
>
> This works if all vlan's are set to 'untagged'.
>
> You could use a shared port for the router with tagged vlan1 and vlan2
> traffic, and then use vlan interfaces in linux for getting the traffic
> from each.
>
> --
> Len Sorensen
> --
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