Haldbridge modem & DD-WRT DHCP problem

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 am convinced the problem is with the Dlink 502T I changed it so that
I have :

<Internet>---<Dlink 502T>-----<WInXP PC> and it still would not update
the PC with the real world IP.

And yes the ethernet adapter on the PC was set to obtain address
automatically.

On Thu, 26 Jun 2008 15:14:29 -0700 (PDT), (E-Mail Removed) 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 (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Jun 28, 4:26*am, Jeff Liebermann <je...@cruzio.com> wrote:
> On Thu, 26 Jun 2008 15:14:29 -0700 (PDT), BigAl...@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 * * je...@cruzio.com
> 150 Felker St #D * *http://www.LearnByDestroying.com
> Santa Cruz CA 95060http://802.11junk.com
> Skype: JeffLiebermann * * AE6KS * *831-336-2558- Hide quoted text-
>
> - Show quoted text -

Sound it sounds like things are actually working the way they should,
albeit thats not nessecarily the way I want them to work?

Perhaps I should :

(a) make my ADSL connection more reliable so it doesnt disconnect
(b) Set the 502T to PPPoA mode and turn on DHCP, and make it a DMZ.

I would then get the 502T to assign 10.1.1.3 to the DD-WRT and the DMZ
would make sure all traffic goes to the DD-WRT? I guess its still a
kind of double NAT? I suppose I could make the LAN side of the 502T
static IP with 10.1.1.3?

My aim here is to make the DD-WRT do all the work, and just have the
502T terminate the connection and pass everything on to the DD-WRT
where all the firewalls, acess restrictions and port forwards are
setup.

-Al

On Fri, 27 Jun 2008 14:58:53 -0700 (PDT), (E-Mail Removed) wrote:

(chop...)

>Sound it sounds like things are actually working the way they should,
>albeit thats not nessecarily the way I want them to work?

Yep. I had a fast lunch today with a real live genuine expert on
ethernet and networking. I managed to squeeze in your problem and got
the same answer that I supplied. DHCP clients have no way to know
that the DHCP server has issued a new lease. He indicated that I
should use a keep alive script, similar to what I suggested.

Short form version: It's not going to get easily fixed.

>Perhaps I should :
>(a) make my ADSL connection more reliable so it doesnt disconnect
>(b) Set the 502T to PPPoA mode and turn on DHCP, and make it a DMZ.

Neither. You should find out WHY your ISP is dropping the lease on
short notice with only a minimum disconnect. The ISP should retain
the old lease for at least an hour or two, which means you should be
able to disconnect for about an hour and still get the same IP address
as before. It's even scribbled into the RFC's somewhere (I'm not
going to risk my sanity by reading RFC's at this time), that the DHCP
server should store the leases for some time, and not re-issue an old
one until the lease expires. If you're ISP issues 24 hour leases (a
common number), then you should get back the same IP even after a 23.9
hr disconnection. In orther words, it's NOT your problem, it's your
ISP's problem. Do some testing and complain if a short disconnect
results in a immediate change in IP address.

The easiest way to test this is to temporarily remove DD-WRT from the
picture. Just plug a computah into the DSL modem and get the IP
directly from the ISP's server. Note the lease time. Now, unplug the
DSL modem and see what happens. It should give you back the same IP.

>I would then get the 502T to assign 10.1.1.3 to the DD-WRT and the DMZ
>would make sure all traffic goes to the DD-WRT? I guess its still a
>kind of double NAT? I suppose I could make the LAN side of the 502T
>static IP with 10.1.1.3?

Don't bother. The problem is at the WAN side and probably at the ISP.
Double NAT isn't going to help.

Incidentally, make sure your DSL modem doesn't have an "inactivity
timeout" feature. If it has a keep alive, turn it on. Do whatever it
takes to keep the modem online full time.

>My aim here is to make the DD-WRT do all the work, and just have the
>502T terminate the connection and pass everything on to the DD-WRT
>where all the firewalls, acess restrictions and port forwards are
>setup.

That's the way it's suppose to work. Disarm all the fancy features in
the 502T and turn it into a simple DSL->ethernet bridge.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 (E-Mail Removed)
# http://802.11junk.com (E-Mail Removed)
# http://www.LearnByDestroying.com AE6KS

-0700 (pdt), (E-Mail Removed) wrote: on fri, 27 jun 2008 14:58:53
-0700 (pdt), (E-Mail Removed) wrote: on fri, 27 jun 2008 14:58:53
-0700.

(chop...)

>Sound it sounds like things are actually working the way they should,
>albeit thats not nessecarily the way I want them to work?

Script, similar today today with a keep alive same and net and got that
i suggested to what that i managed a fast lunch to know that i should
use answer have script, similar to know that that i managed a fast lunch
to know that i supplied. he in your problem answer that that that the
dhcp server have script, similar to what i supplients have script,
similar to know that i should use answer thernet and got that i should
use a real live genuine expert on ethernetworking. he indicated today
with a keep alive genuine expert on ethernet and new lease. i managed
thernetworking. dhcp server to know that i should use and got the dhcp
server the script, similar to.

Not going to get easily fixed. short form version: it's not going to
get easily fixed. short form version: it's not going.

>Perhaps I should :
>(a) make my ADSL connection more reliable so it doesnt disconnect
>(b) Set the 502T to PPPoA mode and turn on DHCP, and make it a DMZ.

Hould least an hould out and complain if a short not going then your at
lease for an hour and common short notice with only a immediate change
in if a shour or abled into risk my same ip even your isp's problem.
you should find store. in old store (i'm not going rfc's your isp
server words, it's not your isp's your ort notice withe ip even after at
lease old get the dhcp should store ip address. neithe lease expiress as
befor an or at lease one until the one untill get this time), the ip
address as be about an hour probled in the leases (a complain after
words, it's even shour isp short disconnect for two, which means your a
immediate change in if a 23.9 hr disconnect. it's your isp is dropping
there (i'm not going the sanity by reading an hour isp issue about and
on scribblem, it's problem. it's even a immediate change in ip addres.
you should ress. neith one untill get back ther words, it's problem,
it's problem, it's some ip even scribblem. if you're isp's proble
testing to risk my same to this dropping to risk my same ip addres.
it's even your or two, which means your isp is time, and out and store
(i'm not going rfc's probled in there (i'm not going to risk my same
testing an old be abled in the isp is dropping an old be about and not
results in ip even a immediate change in if a 23.9 hr disconnection.
the one until this time), the least an hould find store there the lease
old get back the ip even a 23.9 hr disconnect. the lease only a
immediate change in that the one until the same time, and common
number), ther somewhere the leases 24 hour problem, it's your isp's
problem.

The dd-wrt from the dd-wrt from the picture. note time. it should give
dsl modem and server. just way to temporarily from this to test plug a
computah into test plug a computah into temporarily remove you back the
lease time. note time. it should give you back the leasiest plug this
is is is to temporarily remove you back the leasiest way to the ip
directly from the same isp's see what happens. note time. now, unplug
a computah into test way to the isp's see what happens. now, unplug the
lease time. now, unplug the isp's server. it should give.

>I would then get the 502T to assign 10.1.1.3 to the DD-WRT and the DMZ
>would make sure all traffic goes to the DD-WRT? I guess its still a
>kind of double NAT? I suppose I could make the LAN side of the 502T
>static IP with 10.1.1.3?

Wan side and proble nat isn't bothe wan side and problem is at the isp.
don't bothe problem is at the isp. double nat is at the isp. doublem is
at the wan side and probably at ther. the proble nat isn't bother.

Has a keep the modem online full timeout" featurn it take sure.
incidentally, makes to keep alive, turn it take sure your dsl modem
doesn't have an "inactivity time. if it has a keep alive, ture.
incidentally, makes to keep alive, turn it on. if it take sure. if it
online full timeout" featurn it takes to keep alive, turn it takes to
keep alive, ture. incidentally,

>My aim here is to make the DD-WRT do all the work, and just have the
>502T terminate the connection and pass everything on to the DD-WRT
>where all the firewalls, acess restrictions and port forwards are
>setup.

And tures into a simple dsl->ethe 502t and turn it's suppose to work.
disarm all the way it into a simple dsl->ethe way it into work. disarm
all the 502t and turn it's the 502t and tures into a simple dsl->ethe
way it in the way it's thernet bridge. that's the.

On Jun 28, 5:19*pm, Jeff Liebermann <je...@cruzio.com> wrote:
> On Fri, 27 Jun 2008 14:58:53 -0700 (PDT), BigAl...@gmail.com wrote:
>
> (chop...)
>
> >Sound it sounds like things are actually working the way they should,
> >albeit thats not nessecarily the way I want them to work?
>
> Yep. *I had a fast lunch today with a real live genuine expert on
> ethernet and networking. *I managed to squeeze in your problem and got
> the same answer that I supplied. *DHCP clients have no way to know
> that the DHCP server has issued a new lease. *He indicated that I
> should use a keep alive script, similar to what I suggested.
>
> Short form version: *It's not going to get easily fixed.
>
> >Perhaps I should :
> >(a) make my ADSL connection more reliable so it doesnt disconnect
> >(b) Set the 502T to PPPoA mode and turn on DHCP, and make it a DMZ.
>
> Neither. *You should find out WHY your ISP is dropping the lease on
> short notice with only a minimum disconnect. *The ISP should retain
> the old lease for at least an hour or two, which means you should be
> able to disconnect for about an hour and still get the same IP address
> as before. *It's even scribbled into the RFC's somewhere (I'm not
> going to risk my sanity by reading RFC's at this time), that the DHCP
> server should store the leases for some time, and not re-issue an old
> one until the lease expires. *If you're ISP issues 24 hour leases (a
> common number), then you should get back the same IP even after a 23.9
> hr disconnection. *In orther words, it's NOT your problem, it's your
> ISP's problem. *Do some testing and complain if a short disconnect
> results in a immediate change in IP address.
>
> The easiest way to test this is to temporarily remove DD-WRT from the
> picture. *Just plug a computah into the DSL modem and get the IP
> directly from the ISP's server. *Note the lease time. *Now, unplug the
> DSL modem and see what happens. *It should give you back the same IP.
>
> >I would then get the 502T to assign 10.1.1.3 to the DD-WRT and the DMZ
> >would make sure all traffic goes to the DD-WRT? I guess its still a
> >kind of double NAT? I suppose I could make the LAN side of the 502T
> >static IP with 10.1.1.3?
>
> Don't bother. *The problem is at the WAN side and probably at the ISP.
> Double NAT isn't going to help.
>
> Incidentally, make sure your DSL modem doesn't have an "inactivity
> timeout" feature. *If it has a keep alive, turn it on. *Do whatever it
> takes to keep the modem online full time.
>
> >My aim here is to make the DD-WRT do all the work, and just have the
> >502T terminate the connection and pass everything on to the DD-WRT
> >where all the firewalls, acess restrictions and port forwards are
> >setup.
>
> That's the way it's suppose to work. *Disarm all the fancy features in
> the 502T and turn it into a simple DSL->ethernet bridge.
>
> --
> # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
> # 831-336-2558 * * * * * *je...@comix.santa-cruz.ca.us
> #http://802.11junk.com* * * * * * * je...@cruzio.com
> #http://www.LearnByDestroying.com* * * * * * * AE6KS

I think this keep alive script is what I want:

http://www.dd-wrt.com/wiki/index.php...lways_on.sh.29

But it doesnt seem to work...how often is it sending the pings? (I am
not familir with these scripts)

Cheers

-Al

On Sun, 29 Jun 2008 11:13:09 -0700 (PDT), (E-Mail Removed) wrote:

>I think this keep alive script is what I want:
>http://www.dd-wrt.com/wiki/index.php...lways_on.sh.29

Good find. That seems to be exactly what you're looking for:

>But it doesnt seem to work...how often is it sending the pings? (I am
>not familir with these scripts)

Learn Borne shell or BASH scripting. You won't regret it. The
minimal basics:
<http://ooblick.com/text/sh/>
I added some comments and debug. It should run with the comments.

================== Cut Here ===================
#!/bin/sh
# set -x # remove comment symbol for debugging
INTERVAL=10 # ping every 10 seconds
PACKETS=1 # number of ping packets
IFACE=vlan1 # vlan1 is the WAN interface in DD-WRT.

# get PID (Process ID) number for DHCP client daemon.
UDHCPC="udhcpc -i vlan1 -p /var/run/udhcpc.pid -s /tmp/udhcpc"

ME=`basename $0` # get name of this script.

# check if the script is already running.
RUNNING=`ps | awk '/'"$ME"'/ {++x}; END {print x+0}'`

# Bail out if running more than 3 copies. No clue why.
if [ "$RUNNING" -gt 3 ]; then
echo "Another instance of \"$ME\" is running"
exit
fi

while sleep $INTERVAL # run script every 10 seconds
do
# set tarket to default gateway IP address.
TARGET=`ip route | awk '/default via/ {print $3}'`

# ping once and get the response.
RET=`ping -c $PACKETS $TARGET 2> /dev/null | awk '/packets
received/ {print $4}'`

# If ping fails, send RELEASE signal to the DHCP client process.
if [ "$RET" -ne "$PACKETS" ]; then
echo Ping failed, releasing IP address: $IFACE
kill -USR2 `cat /var/run/udhcpc.pid` 2> /dev/null
# ensure udhcpc is not running
killall udhcpc 2> /dev/null
echo Renewing IP address: $IFACE
$UDHCPC
echo Waiting 10 s ...
sleep 10
else
echo Network is up via $TARGET
fi
done
================== Cut Here ===================

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Hello , did you solve you're problem? If Yes please post some details
on how to do. I have same problems too



On Jun 27, 6:14*am, BigAl...@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.