IP address assignment between DSL modem and ethernetLAN card.

[jack765]

I am a computer geek, but not an IT professional. Sorry for posting this question here, but I couldn't find the relevant answer on the internet.

My home PC has on-board LAN (built-in to motherboard), runs WinXP SP2, and connects to internet via DSL modem.

The DSL requires dial-up, with account name & password, and is then assigned an IP address from the ISP. (Must be DCHP, since the IP is different every time I dial-up.)

The PC itself (ethernet card) receives an internal IP address (169.254.etc) from God-knows-where.

The problem: While surfing the internet is fine, but local software cannot initiate communication with outside internet that requires local software to announce its IP. Reason: when the local software announces its IP, it announces the private IP address. When the other party tries to lookup this IP address on the internet, it finds nothing.

Specific example:
1. Although I can do MSN text chat, I cannot start a MSN voice chat invite; it simply doesn't work. Whereas if someone else invites me for MSN voice chat, this works.
2. For networked gaming over TCP/IP (e.g. Diablo, Age of Empire, etc), I cannot host games, as other players cannot join my game. --> If they enter the IP address for my ethernet card, they cannot find the game. If they enter the IP address for my DSL modem, my DSL modem doesn't know a game is being hosted by the PC, so doesn't respond.

How do I get around this problem?
Thanks.

 

[Crowtalks]

You have a dynamic DSL connection. There are a couple of different issues going on here. Dynamic means that your ISP provides you with whatever WAN (wide area network IE: www) address it can grab from their address blocks. These are subject to change. Occasionally if you loose connectivity with the IP, you may be provided a different WAN address. That's kind of like giving out your home address to people, then changing the numbers on the outside of your house. You are NATed (Network Address Translation) which means that your actual IP address (which can be found by START-RUN-CMD, ipconfig/all enter) is changed to the modem's address before it is sent out to the WWW. That is the reason you can't host games, you have a private address, not a public address on your PC...(By the way, anytime you an address of 169.xxx.xxx.xxx, you are not connected to anything. That's a fake address you computer assigns to itself if it can't find it's next hop.)
You need a static lan block or a VPN connection with ddns to publish your PC's address. Crowtalks

 

[JOAMON]

Look at the basics.....since your PC is XP SP2 try turning of the firewall then see if you can host a game. May need to configure advanced settings in the firewall setup or just leave it off.

 

[allteltec]

Are you useing the XP build in PPPoE software, or did you load added software to handle the PPPoE dialup? With XP all ways use the build in. One anser would be to buy a router then you can open up the ports for your games and the router status page will show your www. IP. A router has build in NAT and outher fire walls and is a lot more secure then just useing a ADSL modem.

 

[DrSic]

I'm missing some info to picture it all, but...
How is your modem connected physically with your pc? supposing it is a usb modem connected to the pc, you might as well turn of your nic because you're not using it.
(btw the nic gets a APIP-address in a private range which is build in by MS and is assigned automatically if your nic is supposed to get an ip-address through DHCP but doesn't get a DHCP-offer from a server).
look in your networkconnection window... what do you see? eg. 1394 (firewire dev), LAN (nic), dial-up (which is not your nic but a soft-socket to the modem).if so the software that needs to connect to the internet should not look at the nic but at your modem connection which uses ppp to connect to your ISP.
Your MSN & gaming prob is also a matter of firewall rules (XP?) since the software use specific TCP ports for connection.