Cable Provider Plays Games with IP Address

[fredeis]

My internet service provider is CABLE.

I'm on all the time and use a 4 port linksys router.

On the router i see an IP address in the Status area.

However, sometimes when I run an FTP server, i notice that in addition to my LAN address, i see that there is another weird IP address.

Also, I notice that if try to run a WEB server - I can not using the IP address noted on the LINKSYS.

However, the IP address that I can sometimes pick off the FTP server is addressable for a port 80 web server. It appears that both IP addresses are active simultaneously. However, the second one appears to be short lived and changes.

I understand that my CABLE provider blocks port 80, making it very difficult to serve up a web page - and the easy to use web servers utilize port 80.

Does anyone know how to easily identify this second IP address, how to lock it, how to control it, how to map it...etc etc....

Thanks.

 

[Rockn]

If you didn't buy a static IP address it will always change. They are probably doing some kind of network address translation and your address is showing up as something like 10.0.0.1
Your ISP controls it so unless you buy a static one you are outta luck.

 

[fredeis]

Thank you...

The address that comes back starts with 172 and is not the 10....that you suggessted.

Also, the address that the cable company provides me seems pretty static...maybe it changes only when i reset the router, otherwise, i've kept the same address for months on end.

I agree that they are doing some sort of translation, but i am wondering how i can tap into it and get regular information on it.

 

[Rockn]

Go to Start >Run and type winipcfg. It will probably give you the 172.0.0.1 which is almost like the loopback address 127.0.0.1

 

[fredeis]

actually, the 172 address is not a loopback address becaUSE IT has been addressable from another location...I have occasionally been aware of what the address is because it shows up on the FTP server and occasionally on PC ANYWHERE...in addition to the more static ip address.

the numbers are not zero's as you thought they may be.

 

[Rockn]

Does the current address show up in winipcfg? There are other tools too that you can use and perhaps you can telnet your cable modem and find it's ethernet address.

 

[fredeis]

WINIPCFG shows the local LAN address...192.168.1.110...

I don't know how to see the ethernet address of the cable modem, although i can see the ethernet address of the linksys thruough the tools available on the linksys.

I know what telnet is, i'm not sure how that will reveal the alternative IP address being assigned periodically by the cable provider.

By the way, i spoke to the cable provider and they denied that they were doing this aliasing of IP address.

They do acknowledge blocking port 80

 

[Zee-Way]

Hey Fredeis,

I'm Kris Anderson, Network Tech from Zee-Way Services. We found that if you go to Dynu.com you can sign up for a service called Dynamic DNS.

After you sign up, you will be required to download a file. This file runs on your computer under the task bar. It will monitor your changing IP and update yourname.dynu.com to the new IP.

Kris Anderson
Zee-Way Services