[nldirkz1]

I have been trying to figure out how to transfer my external IP address obtained from my ISP to the WRT54GL router, so I can try the next step and setup a VPN connection. I am struggeling (already) with part one and getting lost in the "world of networking" browsing the forum and wiki

I live in the Netherlands and I have to connect via PPPOA. I can put by ST546 in halfbridge mode (called DHCP SPOOF in the speedtouch). This I understand and works. The ST basically becomes a modem only. When I do this my ST modem gets an IP 10.0.0.138/24 and my computer gets assigned IP 80.101.219.51 by the DHCP server of the ST because in the settings of the ST I can see
DHCP First Address: 80.101.219.51
DHCP Last Address: 80.101.219.51

At this point I can get on the internet just like I could in the normal routed connection where my ST is configured as a modem&router.

When I connect the WRT54GL I have no internet any more and can only login to the WRT54GL configuration pages. Not anymore in the ST modem (but I saw a nice wiki about that howto solve it).

I have a wired setup so I am running a cable from the ST lan port 1 to lan port 1 of the WRT54GL (or should it be the WAN/internet port of the WRT54GL?). I have not made any configuration alterations in the WRT54GL and not yet upgraded the orginal linksys firmware to dd-wrt firmware. The DHCP server of the linksys is running and I have not touched the internet connection settings of the linksys since I figure the Speedtouch is doing that.

I missing obviously something (which with my basic understanding would not be strange) any help is appriciated.

[dave.tchang]

[nldirkz1]

Dave, thanks, its working this is what I did.
From what I understand for the Linksys to function the WAN IP address (your external IP address obtained from your ISP) plus default gateway (internal IP from Speedtouch) need to be on the same subnet mask. (do not ask me why or what it technically means)

step 1.
you need to find your external IP address. I found it by using http://www.watismijnip.nl/. Write it down.

Step 2:
put your ST in half bridge mode, called DHCP SPOOF. This is done via the configuration program you can download from the the ST website.

Step 3:
once the configuration wizard is finished (your internet should function again) you can, log back into the ST (http://10.0.0.138/) and add an additional IP using the webinterface clicking on <home network> <interfactes> <local network>. Choose to add an additional IP. Fill in your external IP address you found under step 1 but change the last number into a 1. for example:
83.96.216.19 become 83.96.216.1
continue to add the subnet mask 255.255.255.0
click <add> and hit <apply>

step 4:
login to the linksys and under internet connection choose static IP and fill out:
internet IP address: <your external IP address>
subnetmask :255.255.255.0
Default gateway: <the address you added in the ST ending with "1")
PRimery DNS: your primery DNS server of your provider
Secondary DNs: your secondary DNS server of your provider.

click save settings. done.

now connect the speedtouch to the linksys wan/internet port and you should have internet again.

The above is the result of cut and paste from sources http://gathering.tweakers.net/forum/list_messages/1272598/0//pppoa%2Chalf%2C and people who actually understand what they are doing. It works.

If somebody can explain if the above set-up is "smart" and "safe" I would appreciate it. This seems the only way to pass on my external IP address to my linksys router on a PPPoA connection.

I hope it helps some people.

[dave.tchang]

[frater]

Just download this configuration wizard and configure it as dhcp-spoof.
Configure your router to obtain an IP automatically.

http://helpdesk.gakijken.nl/site/cm_bestanden/display_bestand.asp?id=10004598

You will get an IP in a /8 network. This way there's a very big chance your gateway is within your network.

If the gateway is outside your network it doesn't mean it doesn't work. It depends on the used firmware.

I think the latest versions of DD-WRT can cope with that situation, but if it doesn't, I can give you a workaround.

[Gadget]

@frater, let's hear about the workaround.

When using the PPPoA spoofing config my laptop works fine when directly connected to the ST546.

ipconfig /all gives me this:
IP: 86.93.x.x
Subnet: 255.0.0.0
Gateway: 195.190.242.9
DHCP server: 10.0.0.138
DNS servers: 195.121.1.34
195.121.1.66

When connecting the Linksys the Status->WAN page shows me the correct WAN IP address. (86.93.x.x)
Also Subnet Mask, Gateway, DNS 1 and DNS 2 are identical as above.

Problem now is that only my WAN IP address can be pinged from the LAN.
All other WAN IP addresses are unreachable.

What can I do to make the Linksys route correctly?

Thx!

[mstombs]

Please see my comments on this 'feature' inherited from Linksys Linux based routers

http://www.dd-wrt.com/phpBB2/viewtopic.php?p=247452

putting this, or fancier versions in your dd-wrt firewall script should be a complete solution

[Gadget]

Big thanks mstombs.
Only three lines of code but very helpfull.
Works like a charm!

In the DD-WRT GUI go to "Administration -> Commands" and paste the code in the box.
Click on "Save Firewall" and done!
Because it's saved in NVRAM it survives a reboot of the router.

[Gadget]

To make the story complete I was stuck with one more problem.
The dhcp-spoof template from the SpeedTouch Configuration Wizard uses a 30 seconds lease time. When I start ping -t command on my laptop this works fine but gives a few "destination not reachable" messages every 30 seconds.
My guess is the linksys is busy renewing the WAN lease and this gives the interrupts.

I solved this by changing the dhcp-spoof template.
I changed the 30sec lease to 432000sec lease.
This way the Linksys sees a 5 day WAN lease and my problems where gone.

I added the modified template.
Edit: Removed attachement, problem is solved.

Hope this helps somebody in the future.

[mstombs]

Good that it works, the 'fancier' scripts only apply the 2 route commands if needed, or try to ensure old routes are cleaned up, duplicate default route commands break things - I don't think this is an issue with dd-wrt

If you have a 30second lease it should be renewed without internet interruption at half-time every 15seconds. If the renew doesn't work there may be an interruption due to to the discovery/offer and accept process at the 30 second interval.

The reason they set a short lease time in half-bridge is that's the only way a new WAN IP can be transferred - if your IP is like mine and you get a new IP every time the DSL drops and reconnects.

With a long lease you will have a problem if you have a dynamic IP and it changes. Curiously windows knows about this sort of problem and sends out lots of dhcp renews if it thinks it has lost contact with its Gateway. There is a script in the dd-wrt wiki to create a simple script to ping something and do similar - there's no way I know for the Linux OS to do this automatically.

[Gadget]

If I type "route" I only see one default route, therefore no need for a fancier script.

I understand what you mean with the risk of a long lease.
In The Netherlands, where I live, this is no big problem because ISP's almost always give you the same WAN IP if you power cycle the modem. (With no guarantee if you look in the contract.)

Interesting that you say the 30 seconds lease must work.
If this is no know bug in the Linksys I guess this mechanism is badly implemented in the SpeedTouch 546v6.

[Gadget]

Because I'm curious I did some more tests.
I changed the lease time on my ST546 to 1 and 5 minutes.
Both lease times gives trouble with the Linksys connected. (Ping -t gives few destination unreachable messages when total lease time expires.)

When I connect my laptop directly to the ST546 and thus getting the WAN IP address I started Wireshark.
Exactly like mstombs said you see, half way the lease time expires, DHCP Request and milliseconds later the DHCP ACK.
Funny thing here is that the request is send from my laptop to 10.0.0.138. The MAC address used belongs to the SpeedTouch.
Thus 10.0.0.138 belongs to the SpeedTouch.

This IP address also shows up when I type ipconfig /all on the laptop! (See picture.)

My guess is the Linksys does NOT send it's DHCP Request to 10.0.0.138 and that's why the renewal process doesn't work as expected.

I'll try to install tcpdump on my Linksys to see if I can make a capture of the WAN interface to analyse this.

Maybe a dd-wrt guru can tell if the DHCP ACK message is handled properly?
If you dissect the DHCP ACK message with Wireshark you see, "Option: (54) Server Identifier" which holds the correct DHCP server IP address.
(In my case 10.0.0.138)

[Gadget]

After testing with a hub between the ST546 and the Linksys WAN port it looks like the Linksys is faulty.
I created a new topic to address this issue.

http://www.dd-wrt.com/phpBB2/viewtopic.php?t=48704