Can't ping ADSL routed pc's from external source - help!!

[Guest]

Hi,

I have two pc's (WinXP SP1 on both) networked through a 4 port ADSL
Router/Modem. I have no problems with the local network, which appears to
work fine and can access the internet from both pc's too. The problem I have
is trying to connect to either pc from an external source; ie a friends
computer. I seem to be able to ping the WAN IP address shown below with no
problem, but cannot ping either pc on the network ....I know the LAN IP's are
no good for this, but don't know what IP address i should enter to ping the
pc's sucessfully. I've heard someone mention NAT but am not sure how to go
about setting it up? is there an easy solution!!

Any help would be appreciated and also prevent me from becoming prematurely
bald!!

WAN
IP Address: 212.84.102.55 Subnet Mask: 255.255.255.0

Computer 1 LAN IP Address: 10.0.0.2 Subnet Mask: 255.0.0.0
Computer 2 LAN IP Address: 10.0.0.5 Subnet Mask: 255.0.0.0

DHCP Server: 10.0.0.2
Default Gateway: 10.0.0.2
DNS Server: 10.0.0.2

Thanks

Neil

 

[Ryan Hanisco]

Neil,

I am sure you'll not appreciate the humor in this, but... it is working
exactly as it is supposed to.

The hard part here is telling you how to do this as every piece of equipment
is different. I can tell you technically what has to be done, but if you
understood that, you wouldn't have the question... so, on that note, here
goes.

The easiest way to do this is to pay for Business Class DSL and have a
number of public IP addresses. Then you would use NAT (Network address
translation) to translate one of the public addresses to one of the private
ones on the inside of your network.

In your case, you probably have a consumer-class DSL which gives you one IP
address. If it is static, you can use PAT (Still usually called NAT, but it
is Port Address Translation). What this will do is let you use the one
public IP address you have and map it to a specific port or address on the
inside. (e.g., 212.84.102.55 on port 20,000 can map to port 80 on 10.0.0.2)

If you don't even have one static IP address, it gets even funkier as you'd
have to use DDNS (a dynamic DNS service) to map a domain name to your
changing IP address and then PAT to resolve to an internal address or port.
This is different on every router and not supported by many. In this case,
I usually just call it a lost cause because of the flaky nature of the
technology.

I hope that gives you enough to examine your options and start looking at
possible configurations. Remember, businesses of any size always go with
option one. It is the most stable of them all.