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Why public IP address changed for home computer depending on which ethernet port is used on motherboard ?

Started by Unknown October 16, 2018
ipconfig /all output from home computer:

(I manually text-edited/filtered out the IPv4 parts for marvel vs nvidia ethernet port):


Today I used this ethernet port:

(marvel):
Ethernet adapter Local Area Connection 8:

   Connection-specific DNS Suffix  . : dynamic.ziggo.nl
   Description . . . . . . . . . . . : Marvell Yukon 88E8053 PCI-E Gigabit Ethernet Controller #3
   Physical Address. . . . . . . . . : 00-01-6C-C8-68-F6
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 212.120.118.72(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.254.0
   Lease Obtained. . . . . . . . . . : Tuesday, 16 October 2018 8:10:05
   Lease Expires . . . . . . . . . . : Tuesday, 16 October 2018 9:10:05
   Default Gateway . . . . . . . . . : 212.120.118.1
   DHCP Server . . . . . . . . . . . : 10.255.235.1
   DNS Servers . . . . . . . . . . . : 84.116.46.22
                                       84.116.46.23
   NetBIOS over Tcpip. . . . . . . . : Disabled

Yesterday/days ago I used this ethernet port:

(nvidia):
Ethernet adapter Local Area Connection 9:

   Connection-specific DNS Suffix  . : dynamic.ziggo.nl
   Description . . . . . . . . . . . : NVIDIA nForce Networking Controller #3
   Physical Address. . . . . . . . . : 00-01-6C-C8-68-F7
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 84.25.113.203(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.254.0
   Lease Obtained. . . . . . . . . . : Friday, 12 October 2018 19:23:46
   Lease Expires . . . . . . . . . . : Friday, 19 October 2018 19:53:46
   Default Gateway . . . . . . . . . : 84.25.112.1
   DHCP Server . . . . . . . . . . . : 10.255.235.1
   DNS Servers . . . . . . . . . . . : 84.116.46.22
                                       84.116.46.23
   NetBIOS over Tcpip. . . . . . . . : Disabled


(Same computer, it has two ethernet ports on it's motherboard, one nvidia chip/component) and one marvel chip/component)

Here is a question for you guys !?:

Why would my home-computer's public IP address change depending on which ethernet port is being used ?!?!?

Perhaps ISP thinks I am using two different home computers and is being "kind" by providing two different IP addresses ?!?

(Thus it may examine ethernet adaptor's mac address of home computer via cable modem, cable modem is probably detecting my home computer's ethernet port/mac address and relaying this information to isp...  ?

Bye,
  Skybuck. 
The question is now what happens if I connect a different computer, say a laptop would it change again ? I don't think so it would probably use 84.25.113.203 again, but laptop's ethernet mac is totally different I presume.

Just hypothesis will have to test laptop and pay attention to this to notice any changes.

Other idea which came to mind is "device spying" by ISP.

Otherwise I have no explanation for this for now...

I may report my findings for laptop later...

Bye,
  Skybuck.
ipconfig /all on german laptop:

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. Alle Rechte vorbehalten.

C:\Users\Hartmanns>ipconfig /all

Windows-IP-Konfiguration

   Hostname  . . . . . . . . . . . . : xxxxxxxxxx-NB
   Primäres DNS-Suffix . . . . . . . :
   Knotentyp . . . . . . . . . . . . : Gemischt
   IP-Routing aktiviert  . . . . . . : Ja
   WINS-Proxy aktiviert  . . . . . . : Nein
   DNS-Suffixsuchliste . . . . . . . : dynamic.ziggo.nl
   Systemquarantänestatus. . . . . . : Nicht eingeschränkt


Drahtlos-LAN-Adapter Drahtlosnetzwerkverbindung:

   Medienstatus. . . . . . . . . . . : Medium getrennt
   Verbindungsspezifisches DNS-Suffix: schunck.nl
   Beschreibung. . . . . . . . . . . : Ralink RT3090 802.11b/g/n WiFi Adapter
   Physikalische Adresse . . . . . . : E0-2A-82-15-63-03
   DHCP aktiviert. . . . . . . . . . : Ja
   Autokonfiguration aktiviert . . . : Ja

Ethernet-Adapter LAN-Verbindung:

   Verbindungsspezifisches DNS-Suffix: dynamic.ziggo.nl
   Beschreibung. . . . . . . . . . . : Realtek PCIe GBE Family Controller
   Physikalische Adresse . . . . . . : 64-31-50-01-BD-47
   DHCP aktiviert. . . . . . . . . . : Ja
   Autokonfiguration aktiviert . . . : Ja
   Verbindungslokale IPv6-Adresse  . : fe80::a95c:c1ce:5f6f:166e%10(Bevorzugt)
   IPv4-Adresse  . . . . . . . . . . : 80.115.146.7(Bevorzugt)
   Subnetzmaske  . . . . . . . . . . : 255.255.254.0
   Lease erhalten. . . . . . . . . . : dinsdag 16 oktober 2018 9:18:36
   Lease läuft ab. . . . . . . . . . : dinsdag 16 oktober 2018 10:18:36
   Standardgateway . . . . . . . . . : 80.115.146.1
   DHCP-Server . . . . . . . . . . . : 10.255.235.1
   DHCPv6-IAID . . . . . . . . . . . : 174338384
   DHCPv6-Client-DUID. . . . . . . . : 00-01-00-01-14-49-76-F6-64-31-50-01-BD-47

   DNS-Server  . . . . . . . . . . . : 84.116.46.22
                                       84.116.46.23
   NetBIOS über TCP/IP . . . . . . . : Deaktiviert

Tunneladapter isatap.schunck.nl:

   Medienstatus. . . . . . . . . . . : Medium getrennt
   Verbindungsspezifisches DNS-Suffix:
   Beschreibung. . . . . . . . . . . : Microsoft-ISATAP-Adapter
   Physikalische Adresse . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP aktiviert. . . . . . . . . . : Nein
   Autokonfiguration aktiviert . . . : Ja

Tunneladapter isatap.dynamic.ziggo.nl:

   Medienstatus. . . . . . . . . . . : Medium getrennt
   Verbindungsspezifisches DNS-Suffix: dynamic.ziggo.nl
   Beschreibung. . . . . . . . . . . : Microsoft-ISATAP-Adapter #2
   Physikalische Adresse . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP aktiviert. . . . . . . . . . : Nein
   Autokonfiguration aktiviert . . . : Ja

Tunneladapter Teredo Tunneling Pseudo-Interface:

   Medienstatus. . . . . . . . . . . : Medium getrennt
   Verbindungsspezifisches DNS-Suffix:
   Beschreibung. . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
   Physikalische Adresse . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP aktiviert. . . . . . . . . . : Nein
   Autokonfiguration aktiviert . . . : Ja

Tunneladapter 6TO4 Adapter:

   Verbindungsspezifisches DNS-Suffix: dynamic.ziggo.nl
   Beschreibung. . . . . . . . . . . : Microsoft-6zu4-Adapter #3
   Physikalische Adresse . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP aktiviert. . . . . . . . . . : Nein
   Autokonfiguration aktiviert . . . : Ja
   IPv6-Adresse. . . . . . . . . . . : 2002:5073:9207::5073:9207(Bevorzugt)
   Standardgateway . . . . . . . . . : 2002:c058:6301::c058:6301
                                       2002:c058:6301::1
   DNS-Server  . . . . . . . . . . . : 84.116.46.22
                                       84.116.46.23
   NetBIOS über TCP/IP . . . . . . . : Deaktiviert


Interestingly enough this laptop remembers wifi hotspot bit of a privacy thing there but ok/

Also IP is definetly different... didnt quit expect that but then again kinda did...  this makes a little bit more sense to me but not much.

Think laptop mac address has something to do with giving it a specific public ip.


Bye, Skybuck
On Tuesday, 16 October 2018 08:27:44 UTC+1, skybu...@hotmail.com  wrote:

Getting different IP addresses when you change ethernet ports is
exactly what you should be expecting.

The service provider is not being "kind" by allocating you two
addresses.  You only get one at a time.

Your MAC address is sent to the service provider's DHCP server at
10.255.235.1 which then allocates you an address and default gateway.
You can follow this process using Wireshark if you want.

The DHCP server remembers your MAC address and if it sees that you
have recently been connected using the same MAC address it tries
to allocate you the IP address that you had before.

Every MAC address that you use will result in a different IP
address.  However, if you try to connect two computers at once
only one of them is likely to get a working connection.

If you don't use a particular MAC address for a while, the DHCP
server will eventually time out and return the address associated
with that MAC to a shared pool from which it will get allocated
to somebody else.

The reason you are getting this behaviour is because you are
using the cable modem in bridge mode and connecting directly
to it.  Most people do not do this!

The usual setups are:

1)  Use cable modem in "router" mode.  The router then allocates
you a private address, usually something like 192.168.x.x
In this mode you can have many computers on your LAN all
accessing the internet at the same time sharing the same IP
address using NAT in the router.  If you need to allow
incoming access on certain ports you set up port forwarding
rules in the router configuration web pages. Some routers will
set up incoming port forwards automatically at the request of
the PC using the PnP protocol.  Alternatively, you configure
a "DMZ" where one of your computers receives all incoming
traffic that is not a reply to outgoing traffic.

2)  Use cable modem in "bridge" mode and connect your own
separate router between the cable modem and the rest of the LAN.
Port forwarding or "DMZ" would be set up as described above but 
in the separate router.  The advantage of a separate router
is that you have a wider choice of products.

In both of the above setups your LAN is protected by firewall
rules in the router (or router part of the cable modem).

In your current setup, you are relying totally on your PC being
immune to hacking attempts from outside, especially if you have
disabled the Windows firewall.

You seem to be making life much more complicated for yourself
than you need to.  I suspect that your Windows setup is broken
in some way.  I can't help much with that as I hardly ever use
Windows.  (I prefer Linux Mint for desktops and Centos for
servers.)

John
skybuck2000@hotmail.com wrote in news:592d5aa3-65c1-4f89-9712-7e15f292dfc1
@googlegroups.com:

> Other idea which came to mind is "device spying" by ISP.
Idiot. Your "public IP" address is assigned by the isp. If you hook into THEIR network (your cable modem) with a different MAC ID, they will assign a different public ip address to it. Pretty basic stuff. Device spying? Grow up. Go learn about tcp/ip AGAIN, cause you missed it the first time through.
jrwalliker@gmail.com wrote in news:e769fb49-503f-4958-a466-ac902849d9b8
@googlegroups.com:

> Getting different IP addresses when you change ethernet ports is > exactly what you should be expecting. >
And this is exactly why you should be sending him off to a mewsgroup where his petty stupid shit is on topic. NOT HERE. He takes stupid to an all new low.