DD-WRT always_on script & Gateway = IP???

Forums › New Zealand Broadband › DD-WRT always_on script & Gateway = IP???

bigal_nz

635 posts

Ultimate Geek
+1 received by user: 32
Inactive user

#24042 13-Jul-2008 22:14

Hi folks,

I have a odd problem with always_on.sh script.

But first some background, my setup is this:

internet>--<302G>--<DD-WRT Router>--<PC>

The problem is that when my modem disconnects, and subsequently reconnects (which happens in the space of a few seconds) the script is not detecting the new IP and therefore not running renew DHCP.

With my very basic skills, i have worked out that, for some reason after the modem disconnects and reconnects, I can still ping the old gateway address, yet I cant ping google (IP or name).

I looked closer at what the DD-WRT is getting from my modem in half bridge:

WAN Config

IP Address : 118.92.137.122

Subnet mask : 255.255.255.255

Gateway : 118.92.137.122

DNS1 : 203.109.129.67

DNS2 : 203.109.129.68

Notice how the Ip Address and the gateway are the same? I am not sure if they are the meant to be the same, but I think that is why the always on script (which tests if the connection is up by pinging the gateway) can still ping the gateway, even if the modem has since disconnected and got a new IP. Does anyone know if (a) I have screwed something up or (b) its behaving this way by design?

The script: http://www.dd-wrt.com/wiki/index.php/Useful_Scripts#Automatic_Connection_Repair_.28always_on.sh.29

LAN Setup

MAC Address00:06:25:C4:81:EF

IP Address192.168.1.1

Subnet Mask255.255.255.0

Gateway0.0.0.0

Local DNS0.0.0.0

WAN Connection Type : Auto Config - DHCP

Router Name : DD-WRT

Host Name : Geek

Domain Name :

Router IP Local Address : 192.168.1.1

Subnet: 255.255.255.0

Gateway: 0.0.0.0

Local DNS: 0.0.0.0

Network Address Server Settings (DHCP) DHCp Type : DHCP Server DHCP Server : Enable

Start IP Address : 192.168.1.100 Static DNS1: 203.109.129.67 Static DNS2: 203.109.129.68

If anyone who can help needs more info please just ask!!! :D Thanks in advance,

-Al

PS: And yes I could just make the script ping one of the DNS servers, but I would like to know why its not working the way its designed!? :D :D :D

PPS: I notice the gateway address is not defined in the 302G either

bigal_nz

635 posts

Ultimate Geek
+1 received by user: 32
Inactive user

#147608 13-Jul-2008 22:43

Things get even more interesting if I use my Linksys AM300 Modem instead of the Dlink 302G.

When using the AM300 it displays a Gateway address that is different to my IP:

AM300:

PPP Login:	Up
Internet IP Address:	118.93.33.54
Internet Netmask:	255.0.0.0
Internet Gateway:	203.109.128.90

Then in my DD-WRT instead of the gateway and IP being the same I get:
IP Address 118.93.33.54

Subnet Mask 255.255.255.0

Gateway 118.93.33.254

DNS 1 203.109.129.67

DNS 2 203.109.129.68

That creates a whole new question - why is the gateway listed by the AM300 different to what the DD-WRT router shows? Maybe something to do with having to be on the same subnet?

-Al

bigal_nz

635 posts

Ultimate Geek
+1 received by user: 32
Inactive user

#147612 13-Jul-2008 22:49

Interestingly the script works with the AM300, so the problem lies squarly with the Dlink 302G and it not passing any form of gateway address to the DD-WRT router......

webwat

2036 posts

Uber Geek
+1 received by user: 145

Trusted

#148720 17-Jul-2008 02:24

It should not use "Auto Config - DHCP" for the WAN, must always be PPPoA. I would say clear it to factory default and start again, perhaps test any NAT port forwarding or DMZ settings you can find instead of half-bridge.

Time to find a new industry!

bigal_nz

635 posts

Ultimate Geek
+1 received by user: 32
Inactive user

#148729 17-Jul-2008 07:22

No it shouldnt - the modem is in half bridge mode, it terminates the PPPoA connection and then passes the real world IP (via DHCP) to the Router.

rphenix

990 posts

Ultimate Geek
+1 received by user: 127

ID Verified

Lifetime subscriber

#151345 25-Jul-2008 16:11

The free via xtra 302g in half bridge is poor at best I remember trialing several we ended up using a US Robotics USR9105 which worked out to be a very good router for half bridge mode. Nowadays I would just get a Draytek Vigor 110 ADSL modem (yes its a real modem) read here and here