🚀 go-pugleaf

On Thu, 26 Jun 2008 15:14:29 -0700 (PDT), BigAl.NZ@gmail.com wrote:

>Hi All,
>
>Hope someone here can help. I am having a problem with the following
>setup:
>
><Internet>----<Dlink 502G ADSL modem>-----<DD-WRT router>-----<Windows
>XP PC>
>
>Dlink 502G : in half bridge mode, so as I understand it, it should
>terminate my PPPoA connection, but pass on the real world IP to the DD-
>WRT. Address to access setup pages is 10.1.1.1. Is being assigned
>dynamic IP's by ISP.
>
>DD-WRT : Getting the real world IP from the Dlink 502G ok. Setup pages
>is 192.168.1.1. Assigns IP's to clients in the range 192.168.1.100.
>
>Now the problem is that when the Dlink 502G resynchs, for whatever
>reason, the new IP is not being passed on to the DD-WRT. I can fix
>this by manually going into the DD-WRT setup pages and clicking on
>DHCP renew, but I am assuming it shoud be updating the IP after a
>resynch automatically?
>
>Anyone have any suggestions?
>
>I will try to post some links to screen shots of the setup later.
>
>Cheers
>
>-Al
>PS: DD-WRT running on Linksys v1, V24 stable.

I see that going from v23 to v24 didn't help.
The 192.168.1.xxx IP's are not involved.  Those are the LAN side IP's
that are assigned by the DHCP server in the DD-WRT router.  That's
working.

What's apparently not working is the WAN side DHCP client (not
server).  A few problems.
1.  When you power cycle the DSL modem, there should be no change in
IP address.
2.  If your ISP uses an ATM disconnect (from the modem) to issue a new
IP address, the DHCP client (in DD-WRT) will not notice until it's
time to renew the DHCP lease.  The only way that's going to happen is
if you power cycle BOTH devices or force a renewal from the setup
pages.
3.  There is no mechanism for the DHCP server to inform the client
that it's time to renew BEFORE the lease expires.  For example, if the
DHCP server issued a lease for 24 hours, the client will try to renew
at 12 hours and will not request a new IP until the full 24 hours are
up.
4.  There are kludges to solve this problem.  One is a simple shell
script that tests for connectivity to the ISP gateway.  If it fails,
it forces at a WAN side disconnect:
  ifconfig vlan1 down
followed by a reconnect:
  ifconfig vlan1 up
which I think (not sure) initiates a new DHCP negotiation.  I can try
it here, but not for a few days.  Bizzzzeeeee.


-- 
Jeff Liebermann     jeffl@cruzio.com
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