Re: DHCP over bridge between WiFi and wired
On Thu, Jan 08, 2004 at 10:30:47PM -0700, Barak Pearlmutter wrote:
> I have a WAP which serves DHCP requests.
> I have a laptop with an 802.11b interface. The laptop connects
> to the WAP and gets its IP address via DHCP.
> I have another device (Grandstream BudgeTone-101, a non-wireless SIP
> phone) which uses DHCP as it boots.
> The laptop has an otherwise-unused wired ethernet interface.
> I would like to use the laptop as a bridge, thus allowing the SIP
> phone to plug into the laptop while I'm laying in bed.
>
> $ grep -A9 br0 /etc/network/interfaces
>
> iface br0 inet dhcp
> pre-up egrep --silent '^3c59x' /proc/modules || modprobe 3c59x
> pre-up /etc/init.d/pcmcia start || true
> pre-up cardctl insert || true
> pre-up ifconfig eth0 down || true
> pre-up ifconfig eth1 down || true
> bridge_ports all
> bridge_maxwait 5
> bridge_stp on
>
> The bridge seems to work fine, except that the SIP phone never gets
> its IP address. Ie DHCP does not seem to completely cross the bridge.
>
> Any hints?
Not really hints, but I've seen this on a bridge running iptables. I
assumed it was the iptables rules not letting DHCP through. I didn't go
any further as I was always going to put a DHCP server on the other side
of the bridge anyway. Perhaps you could run ethereal and grab a trace
to find out if any DHCP gets across at all.
But it's strange. I didn't think a bridge knew anything about such
high-level protocols. I know that with different subnets, there is DHCP
relay, but I don't think that applies here.
I'd be interested to know what you find out.
A
--
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