telnet from romote pc to adsl server

[Lux Zhang]

On 22/05/07, Tim <ignored_mailbox at yahoo.com.au> wrote:
>
>
> Lux Zhang:
> >>> I need telnet to access adsl server.
>
> Tim:
> >> Really bad idea.  Telnet is a really insecure protocol.  If you can
> >> use ssh, use it, instead.
>
> Lux Zhang:
> > I have no choice, the modem can only handle telnet
>
> Unless it's the modem, itself, that you're telnetting to, then that's
> wrong.
>
> A telnet server is usually something running on a computer (and that
> seems to be what you've described), all a modem/router has to do is
> forward the right port number through to the computer.  The port number
> is whatever you choose, you don't have to use defaults, and the modem
> doesn't care what goes through that port (telnet, SSH, HTTP, or anything
> else).
>
> If it is the modem that you need to telnet to, a far safer solution
> might be to disalllow the modem to receive WWW telnet connections,
> forward a SSH connection through to a PC inside your LAN, remote connect
> to it in a secure manner, then telnet from that internal PC to your
> modem.


Thanks Tim,

The road is

remote PC(External) -> internet ->modem->router->telnet/ftp/www server PC
 (internal)

I set address forward for ftp/telnet/www in modem BUT ONLY ftp/www in
router, did not set (overlooked) the address for telnet. After set the
addresses in both modem and router, the PC server can be accessed from the
remote (external) computer.





> But  with remote  telnet I got this
> >
> > [zhang at tring ~]$ telnet 79.15.54.181  7777
> > Trying 79.15.54.181...
> > telnet: connect to address 79.15.54.181: Connection timed out
> >
> > In fact the server did show any response
>
> And does that work if you try telnetting to port 7777 on a machine
> inside your LAN rather than one outside it?  I saw your prior message
> saying it worked inside your LAN, but 7777 is an unusual port to play
> with.  Was it the same port number that you tested before?


I set this on the internal sever PC (opened port tcp/7777 in server PC and
modem and router), BUT it is not working when access it from remote external
PC to the internel server, I roll back to the default port

The default, for Fedora, is to run a firewall, so it could be blocked on
> the machine running your server, itself.
>
> --
> (This box runs FC6, my others run FC4 & FC5, in case that's
> important to the thread.)
>
> Don't send private replies to my address, the mailbox is ignored.
> I read messages from the public lists.
>
>
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