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Warning/Disclaimer: Telneting to your Alcatel Speed Touch Pro DSL Modem can be very dangerous and you should be extremely careful when executing commands in the telnet interface. Have your settings written down before you begin and be prepared to reset your modem to factory defaults in case you execute an unwanted command. Red Hat does not support Alcatel products. This article is provided as is and Red Hat is not responsible for the misuse of this article or damage to equipment as a result of following this article.
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The configuration dealt with in this article has the following networking scheme for a home-based network:
| - System 1 - 10.0.0.5 [Linux]
ISP (WWW) <=> Speed Touch Pro <=> Private Network ---| - System 2 - 10.0.0.10 [Linux]
68.22.11.23 10.0.0.138 10.0.0.x | - System 3 - 10.0.0.15 [Linux]
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The Speed Touch Pro is configured to dial the Internet Service Provider (ISP) automatically and maintains an "Always On" status. The modem takes care of obtaining the public facing IP address and performs all the Network Address Translation (NAT)/Port Address Translation (PAT) for the private network.
In order to set-up port forwarding on the Alcatel Speed Touch Pro DSL modem, you will need to telnet to the modem and execute certain commands. This article assumes the following:
- Your modem is already configured for your DSL Internet Service Provider (ISP), which is out of the scope of this example.
- You have the telnet client installed on your system.
- You have the SSH server packages installed, configured to listen on port 22 (default), and currently running.
- The default IP address is 10.0.0.138 (or you know what your modem's private IP address is).
- You have a basic understanding of Network Address Translation (NAT) and Port Address Translation (PAT).
- Your network is set up in such a way that you can access (telnet) your modem from the Linux system on the private network.
The following example will show you how to:
- Telnet to your modem on the default IP address
- Create a NAT entry on port 22
- Save your configuration
- Exit the session
For the purpose of this article, we will set-up port forwarding for SSH, which uses port 22 by default and the TCP protocol, on System 3, IP address of 10.0.0.15. First we will telnet to 10.0.0.138 with the user
alcatel. You should get a prompt similar to the following:
Note: Unless you have accessed the HTML based interface by pointing your browser to http://10.0.0.138, there is no password set. Hitting the
[Enter] or
[Return] key should allow you to enter the telnet interface.
$ telnet 10.0.0.138
Trying 10.0.0.138...
Connected to 10.0.0.138.
Escape character is '^]'.
User : alcatel
SpeedTouch (00-70-A0-06-70-F6)
Password : ############
------------------------------------------------------------------------
*
* ______
* ___/_____/\
* / /\\ ALCATEL ADSL MODEM
* _____/__ / \\
* _/ /\_____/___ \ Version 3.2
* // / \ /\ \
* _______//_______/ \ / _\/______ Copyright 1999-2000.
* / / \ \ / / / /\
* __/ / \ \ / / / / _\__
* / / / \_______\/ / / / / /\
* /_/______/___________________/ /________/ /___/ \
* \ \ \ ___________ \ \ \ \ \ /
* \_\ \ / /\ \ \ \ \___\/
* \ \/ / \ \ \ \ /
* \_____/ / \ \ \________\/
* /__________/ \ \ /
* \ _____ \ /_____\/
* \ / /\ \ /
* /____/ \ \ /
* \ \ /___\/
* \____\/
*
-----------------------------------------------------------------------
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To get a list of commands, type
help at the prompt:
=>help
Following command groups are available :
config system software ip phonebook
nat cip ppp pptp bridge
td dns dhcp
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We want to enter the
nat menu, so enter
nat, then we type
help again to get a list of commands. Also, you can
list your current NAT/PAT settings by typing
list at the command prompt.
=>nat
[nat]=>help
Following commands are available :
enable disable list create delete
defserver applist bindlist bind unbind
save flush load help exit
[nat]=>list
Indx Prot Inside-address:Port Outside-address:Port Foreign-address:Port Flgs Expir State Control
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Next, we
create a NAT/PAT entry. For this example, we use the following:
- protocol = tcp
- inside_addr = 10.0.0.15 (which is System 3)
- [inside_port] = 22 (default SSH port)
- outside_addr = 0.0.0.0 (any IP address)
- [outside_port] = 22 (port that SSH listens for)
After we enter this information, you can execute
list to verify that your entry is correct. You will be prompted for the information after you type
create and hit
[Enter].
[nat]=>create
protocol = tcp
inside_addr = 10.0.0.15
[inside_port] = 22
outside_addr = 0.0.0.0
[outside_port] = 22
[nat]=>list
Indx Prot Inside-address:Port Outside-address:Port Foreign-address:Port Flgs Expir State Control
1 6 10.0.0.15:22 0.0.0.0:22 0.0.0.0:0 template
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To save your settings, type
save at the command prompt. This will not return any output:
To exit the telnet interface, use the following key combination:
Ctrl+], then type
quit at the telnet prompt.
Your modem should now allow you to SSH to your system from an outside address as long as it is connected to the Internet. The modem will simply forward any request for SSH (port 22) to the system you configured this for, which is 10.0.0.15 in this example. The system listening for the request will, of course, require SSH authentication.
