Teksavvy cable modems

[Lennart Sorensen]

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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