Re: Telnet to Modem/Bridge

Hi JF,

Thanks for the reply.

The scenario you just described is applicable when the modem is configured as a router. But if I understand correctly, the scenario will be different if the modem is configured as a bridge since the PC will be the one to initiate the PPPoE connection. After PPPoE has been established, the PC will be assigned a new IP address that might not belong to the subnet of the modem.

My question now is: How can the PC access the telnet interface of the modem? If the PC sends packet to the modem's IP address, will the modem/bridge be able to identify the packet and send response to the PC?

Thanks, Ina

JF Mezei wrote:

snipped-for-privacy@hotmail.com wrote: > > What I can't understand is this: > > If the modem acts as a bridge, the PC connected to it will initiate the > > PPPoE connection. After the PPPoE has been established, the PC will > > have a new IP address. How can it still be able to access the telnet > > interface of the modem? > > > If you setup your router to be a NAT/PAT device, here is how it works: > > Your router has two distinct IP interfaces. One facing the internet, and > one facing your LAN. Both are independant. > > [INTERNET]------- [ 204.206.149.21]-ROUTER-[10.0.0.1]------[LAN] > > Your Router negotiates via PPPoE (or DHCP) an IP with the ISP. It uses that > IP on its WAN facing interface. (WAN= internet) > > It has a fixed IP that you've configured on your LAN. That IP doesn't > change. Your Router can either supply an IP (via DHCP) to your PC or your > PC can use a fixed IP, in both cases, the PC would have an IP that is > within the same subnet as the Router's LAN-facing IP (in the above case a > 10.* IP) > > > Say your PC is 10.0.0.2 . It connects to 72.14.205.103 (google). > > Your Router converts the packets sent by your PC, replacing the "from" IP > (10.0.0.2) with the IP of its WAN-facing interface (204.206.149.21). So > Google sees a call coming in from 204.206.149.21. So responses from google > go to 204.206.149.21. When it reaches your router, the router has smarts in > it that know that the response goes to 10.0.0.2 and your pC then gets the > packet. > > > If your pC wants to connect to any host on the internet, it sends it to its > normal internet IP address. If it wants to talk to the router, it connects > to the LAN side IP address of the router 10.0.0.1. Also, you need to tell > your PC that the default route (gateway) is 10.0.0.1 (your router's LAN > side IP). This tells the PC that any packet destined outside the LAN's > subnet is to be forwarded thorugh the router.
Reply to
en.nui
Loading thread data ...

Correct.

Not sure if Windows is able to do this. But on a real operating system, you could configure multiple interfaces on the same ethernet device.

So, you would have a 10.0.0.2 with subnet of 10.0.0.0/8 and then the interface configured by the PPPoE software with some random IP address.

If you try to talk to 10.0.0.1, the computer should then use the first interface and send out real TCPIP packets to the modem destined for the modem's IP address.

If you try to talk to the internet, you will be sending packets out to a pseudo interface that converts the packets to PPPoE stuff and sends it out to the modem which then forwards those packets over to the DSLAM/BAS.

If your computer is unable to have multiple interfaces, then you can't really do this. You might be able to if you insert a second ethernet card and configure a new IP interface on that one.

try "ifconfig -a" from a command mode in windows. It should list its internet interfaces.

Reply to
JF Mezei

Hi JF,

Thanks for the explanation. I'll check if Windows can support multiple interfaces on the same ethernet device.

Thanks, > snipped-for-privacy@hotmail.com wrote:

Reply to
en.nui

Windows is a real operating system.

Reply to
Mike

"Mike" wrote in news:dnZdh.2525$Ca.1119 @read2.cgocable.net:

Do you know if Windows will accept more than one interface per ethernet device?

Reply to
Tegger

"Mike" wrote in news:dnZdh.2525$ snipped-for-privacy@read2.cgocable.net:

Windows is an interface *not* an operating system: X Windows is an interface, Windows 9x, Windows 2000, Millenium, Windows XP, Windows NT, OS X all include a windows interface. In the first case, it's an addon; in the others, It's an attempt to remove the need filled by the command shell in *nix - Unsucessfully and with less functionality btw.

Reply to
chuckcar

chuckcar wrote in news:Xns9892B3A8AB613chuckcar@

194.177.96.26:

Whoa buddy! That's officially X-Window, NOT "X Windows"!

X-Window is a server, or so says its documentation and error messages.

Reply to
Tegger

Tegger wrote in news:Xns9892CE562FC03tegger@

207.14.116.130:

Sorry,no hyphen. My mistake. It's just "X Window".

formatting link
(Hey JF, the link above has some mention of VAX and OpenVMS, in case you're interested.)

Reply to
Tegger

Tegger wrote in news:Xns9892CE562FC03tegger@207.14.116.130:

No, it's called X Windows at the MIT ftp site (where it was developed) and in the documentation. The plural use refers to panes existing simultaneously (along with multiple, scrolling desktops in X as it's sometimes called) Yes it runs *as* a server, so do most background tasks in *nix. What's your point? it's still *not* an operating system.

Reply to
chuckcar

X-window is a protocol. It provides a server (the terminal/display device) and clients (the applications). At both ends, there are standard APIs for applications. There is also a window manager which can run on a client or on the server machine which handles window decorations, window movement, resizing, iconisation etc.

It is the application which connects to the terminal, hence the unusual client/server definitions.

Reply to
JF Mezei

Tegger wrote in news:Xns9892CFB18FDAFtegger@207.14.116.130:

Try this, it's more likely written by people who know what they're talking about:

formatting link
the X server for intel/pc clone machines.

Reply to
chuckcar

Yes.

Reply to
Geoffrey Welsh

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.