Puzzling issue - External IP on LAN ?

TeddyTed · Post by **TeddyTed** » Sun Dec 10, 2006 5:42 pm

Hello all,

Lately I’ve notice something strange on my LAN at home I’m never notice before.
In command prompt I ran “net view” command to see all computers on the LAN. I then tried to ping the machines by “computer name” and I keep getting an external IP address 209.86.xxx.xxx. This happens with all my machines.
My network consists of the following:
Router:Linksys WRTP54G
Switch: Linksys 8 port EZXS88W
Modem: RCA DCM425
Router doing DHCP
ISP: EarthLink Timewarner
Simple straight forward connection: modem to router and connection from router to switch.
1 PC running Win 2K server , 2 PCs running Win 2k Pro and 3 PCs machines running Win XP Pro (2 notebooks & 1 desktop)
I checked my router and haven’t notice anything strange but I may just be over looking something.

Any advice/suggestions would be appreciated.

Thanks

TB

koldchillah · Post by **koldchillah** » Mon Dec 11, 2006 11:36 am

Is your server running Active Directory & DNS by chance?

TeddyTed · Post by **TeddyTed** » Mon Dec 11, 2006 11:51 am

No, and this happens even if the server is turned off.

koldchillah · Post by **koldchillah** » Mon Dec 11, 2006 12:01 pm

Do you have the IP address of the router listed as the DNS provider for the client workstation network adapters?

Post by **YeOldeStonecat** » Mon Dec 11, 2006 12:03 pm

If you go to whatismyip.com
Does that IP address look familiar?

TeddyTed · Post by **TeddyTed** » Mon Dec 11, 2006 1:17 pm

I did check out IP address (209.86.xxx.xxx) and it seems to be associated with earthlink (my ISP). I get the same reply IP address for all machines on the LAN.
Also, the IP address for earthlink's DNS servers are 207.69.188.186 & 187

Post by **YeOldeStonecat** » Mon Dec 11, 2006 1:22 pm

By chance are your PCs each set with a PPPoE connection?

TeddyTed · Post by **TeddyTed** » Mon Dec 11, 2006 1:30 pm

nope... I've got some configured with a static IP and some with automatically obtain an IP.
My rouuter is not using PPPoE.

Post by **YeOldeStonecat** » Mon Dec 11, 2006 1:57 pm

On cable or a business DSL?

PCs still getting private IPs behind the Linksys NAT (such as 192.168.1.xxx)...or is the Linksys running in router mode with them getting public IPs?

TeddyTed · Post by **TeddyTed** » Mon Dec 11, 2006 2:08 pm

the PCs are using private IPs and the Linky is running is router mode.
Let me also mention this because it may ring a bell.
On the LAN I'm unable to connect to remote desktop/terminal server using machine name but i can connect using the local IP address (192.168.15.xxx)

TeddyTed · Post by **TeddyTed** » Mon Dec 11, 2006 2:11 pm

YeOldeStonecat wrote:On cable or a business DSL?

I'm using regular Cable.

koldchillah · Post by **koldchillah** » Mon Dec 11, 2006 3:35 pm

In 90% of my setups, the DNS information is received by the router from the cable modem and then the router just hands out it's own IP address for DNS to client workstations. Only on DSL setups w/ Bellsouth have I seen the public DNS servers showing up on the clients via DHCP.

If static IP's on the clients, try manually changing their DNS address to point to the router just as your gateway is already set.

by chance is NetBIOS over TCP/IP turned on?

Post by **YeOldeStonecat** » Mon Dec 11, 2006 4:55 pm

TeddyTed wrote:the PCs are using private IPs and the Linky is running is router mode.

Double check that...by default they're usually in "gateway" mode. Router mode is usually used on larger networks, and wide area networks...where one large network is subnetted.

If you run an IPCONFIG /ALL..what do you get for info?

Wether routers use themselves for the DNS server, or simply hand out your ISPs DNS servers to clients, depends on the make/model of router..even the firmware version. Some do, some don't.

Maybe go around into TCP properties, advanced, WINS tab, and "enable netbios over TCP/IP".