ST780 WAN through LAN

märts 11th, 2009 | Filed under Rest of the World

I managed to get hands on a SpeedTouch 780 ADSL2+ modem that has 4 LAN ports, USB, DSL, 2 ATA and PSTN port. I was very intrigued by this device mostly for its ATA ports, because I wanted to use it for my telephone setup.

Unfortunately, I do not have ADSL connectivity at my home, only Wimax, which is connected through a Power over Ethernet device and a LAN cable. Therefore I was trying to find out, if ST780 can connect to internet through one of it’s LAN ports.

Turns out that it can, only one LAN port (only possible on ports 2 through 4) has to be reconfigured to WAN port, which has to be done over CLI (telnet interface). Following configuration is taken from here and parsed to be copy-paste into CLI (typing it was a bit pain, because my terminal did not support backspace nor delete).

For firmware 6.1 and up.

First, to start CLI, you need telnet. Depending on your OS, this can be different, but basically start your favorite terminal (Konsole, cmd.exe, etc) and type:

Then paste the following to clean up all interfaces:

Now we delete current configuration for port 4:

And then create a WAN ethernet interface:

Follow this up with IP interface:

If you need MAC cloning (e.g your cable modem is locked to your computer’s MAC), enter this line too (of course, change it to your computer’s MAC address):

And bring up the interface:

We also enable NAT on that interface:

Next we configure DCHP client on that port:

Finally, save everything

For backup purposes, you might desire copying the user.ini from the device:

fill in username and password, and get the user.ini:

Now you should reset your router for it to acquire new IP address (thanks Abbas)

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  1. Jelle Haandrikman
    nov. 11th, 2010 at 08:49
    Reply | Quote | #1

    Thanks for this overview. I will try this on my old ST-780.

  2. Abbas
    apr. 9th, 2012 at 01:09
    Reply | Quote | #2


    I followed the steps and couldn’t have the expected result, would you kindly help to troubleshoot please?

    Here are the the steps:

    Another question, which mac addr do I have to put? modem’s one?


    Username : Administrator
    Password :

    ______ SpeedTouch 780
    / /\
    _____/__ / \
    _/ /\_____/___ \ Copyright (c) 1999-2007, THOMSON
    // / \ /\ \
    _______//_______/ \ / _\/______
    / / \ \ / / / /\
    __/ / \ \ / / / / _\__
    / / / \_______\/ / / / / /\
    /_/______/___________________/ /________/ /___/ \
    \ \ \ ___________ \ \ \ \ \ /
    \_\ \ / /\ \ \ \ \___\/
    \ \/ / \ \ \ \ /
    \_____/ / \ \ \________\/
    /__________/ \ \ /
    \ _____ \ /_____\/
    \ / /\ \ /___\/
    /____/ \ \ /
    \ \ /___\/


    {Administrator}=>:ppp relay flush
    {Administrator}=>:ppp flush
    {Administrator}=>:eth flush
    {Administrator}=>:atm flush
    {Administrator}=>:atm phonebook flush
    {Administrator}=>:eth bridge ifdelete intf=ethport4
    {Administrator}=>:eth ifadd intf=eth_wan
    {Administrator}=>:eth ifconfig intf=eth_wan dest=ethif4
    {Administrator}=>:eth ifattach intf=eth_wan
    {Administrator}=>:ip ifadd intf=ip_wan_eth dest=eth_wan
    {Administrator}=>:ip ifconfig intf=ip_wan_eth status=up
    {Administrator}=>:ip ifconfig intf=ip_wan_eth hwaddr=00:14:7f:eb:d5:82
    {Administrator}=>:ip ifattach intf=ip_wan_eth
    {Administrator}=>:nat ifconfig intf=ip_wan_eth translation=enabled
    {Administrator}=>:dhcp client ifadd intf=ip_wan_eth
    {Administrator}=>:dhcp client ifconfig intf=ip_wan_eth metric=5 dnsmetric=5
    {Administrator}=>:dhcp client rqoptions add intf=ip_wan_eth option=dhcp-lease-t
    {Administrator}=>:dhcp client rqoptions add intf=ip_wan_eth option=dhcp-renewal
    {Administrator}=>:dhcp client rqoptions add intf=ip_wan_eth option=dhcp-rebindi
    {Administrator}=>:dhcp client rqoptions add intf=ip_wan_eth option=subnet-mask
    {Administrator}=>:dhcp client rqoptions add intf=ip_wan_eth option=classless-st
    {Administrator}=>:dhcp client rqoptions add intf=ip_wan_eth option=default-rout
    {Administrator}=>:dhcp client rqoptions add intf=ip_wan_eth option=classfull-st
    {Administrator}=>:dhcp client rqoptions add intf=ip_wan_eth option=domain-name-
    {Administrator}=>:dhcp client ifattach intf=ip_wan_eth


    Result after that:


    Pinging [] with 32 bytes of data:

    Reply from Destination host unreachable.
    Reply from Destination host unreachable.

    Ping statistics for
    Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
    Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

  3. Laas
    apr. 9th, 2012 at 09:36
    Reply | Quote | #3

    First – the MAC address line is only needed if your ISP locks your connection to your MAC address (which some do) and is irrelevant otherwise. In such a case this MAC must that computer’s MAC that you can successfully connect with (and probably you should change your computer’s MAC afterwards so that no conflicts arise).
    If you put in your modem’s MAC, then you probably created some mess on that port (both ends with the same MAC etc).

    Best bet is to reset your configuration to factory settings and start over. If all is done, then you can verify that you get DHCP lease from upserver with dhcp client iflist command. And possibly renew the lease with dhcp client ifrenew ip_wan_eth

    In any case the ST780 manual can be helpful. Googling for Thomson ST780 CLI brought up this pdf.

    PS. I went over the post and tried to explain better what is going on. Hope this helps too.

  4. Abbas
    apr. 10th, 2012 at 05:13
    Reply | Quote | #4

    The thing that was missing on my steps is: reset the modem before connection to the router (mandatory to have a new IP)

  5. Sharp
    mai 23rd, 2012 at 11:41
    Reply | Quote | #5

    Does the WL and VoIP functions still work after this reconfiguration ?

  6. Laas
    mai 23rd, 2012 at 13:00
    Reply | Quote | #6

    I can’t really vouch for it as I abandoned my VoIP setup (mobile phone is enough for me), but I’d guess that VoIP lives on top of what ever connectivity is configured in the router and thus should work (as it is configured to send voice to VoIP servers by name, not by specific network interfaces).

    But you could always back up your current config and give it a try. And keep us posted of your results.

  7. Sharp
    mai 23rd, 2012 at 13:19
    Reply | Quote | #7

    Will do, thnx

  8. cloneman
    veebr. 10th, 2014 at 04:57
    Reply | Quote | #8


    Just wanted to thank you for posting this. I used this setup for over a year with no problems, since I upgraded to VDSL and I could no longer use the ST780 as a VoIP+modem combo, I wanted to use it as VOIP only.

    Sometimes when my internet connection disconnects the ST780 doesn’t realise it and doesn’t reconnect the VoIP, I have to reboot it. That is my only problem with the setup.

  9. Carlos
    mai 23rd, 2014 at 23:30
    Reply | Quote | #9

    Manually configure the addresses of the newly created port ip_wan_eth.

    since my internet service is no DHCP