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does my modem know my public IP address ?

Last response: in Toms Network
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August 31, 2013 1:24:16 PM

hi all
I am using normal cisco linksys modem.
the default setting which is 192.168.1.0/24.

assume my public IP address is 10.10.10.10,

does my modem know this IP initially ?

More about : modem public address

August 31, 2013 1:32:26 PM

No. Most with ISP's the modem picks up an IP through dhcp. They may set up your specific modem to get an IP, but it really depends on the ISP.
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August 31, 2013 1:46:58 PM

10.10.10.10 is not a public IP
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August 31, 2013 2:06:32 PM

this post is just an example.

ok, if I get public IP address through ISP DHCP,

if my computer send a packet to the internet, the packet will carry source IP address of 192.168.1.100,
so at which level the source IP address will be changed to public IP ?

what is the interface which identify my public IP address ?
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September 2, 2013 11:13:48 AM

It usually the one of the following three devices:

if you have a modem connected to a router and the WAN IP of the router has a public IP, it is the Router.

if you have a modem connected to a router and the WAN IP of the router has a local IP, it is the Modem.

if you have an all-in-one modem/router, it is the Modem/Router
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September 2, 2013 9:19:01 PM

actually I am using linksys DSL which linked to phone line and to Network Interface Device.

so does that mean the public IP address is assigned to my modem ?
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September 3, 2013 1:13:58 AM

Yes, since it is most likely a DSL modem/router
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September 4, 2013 9:33:56 AM

oudmaster said:
this post is just an example.

ok, if I get public IP address through ISP DHCP,

if my computer send a packet to the internet, the packet will carry source IP address of 192.168.1.100,
so at which level the source IP address will be changed to public IP ?

what is the interface which identify my public IP address ?


The WAN interface of your router or the WAN interface of the modem/router combo used will be the first interface to identify you by a public IP address. Internal IP adresses are masked by using Network Address Translation.
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September 4, 2013 12:56:17 PM

OK it is clear,

so if you try to ping a public IP address in the other side of the world successfully, that means your ping packet is reaching their modem ? correct ?
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September 4, 2013 1:03:35 PM

Your remote friend should go to a place that displays their public IP address (IPchicken.com or whatismyIP.com) then you on the other side of the world could ping it. Only if pings are allowed. By default most home routers are turned off.

Have them look in their router settings for something like "Filter anonymous Internet Requests" is unchecked ( LinkSys, I know I know...)
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September 4, 2013 1:19:52 PM

interesting,

so if we could manage to reach their modem, then they can do routing to let us access their private network ? right ?
is that possible ? (if we just use simple DSL modem) and both have static IP.

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September 5, 2013 10:16:05 AM

oudmaster said:
interesting,

so if we could manage to reach their modem, then they can do routing to let us access their private network ? right ?
is that possible ? (if we just use simple DSL modem) and both have static IP.



Modems are just another device between their router on their end . Modem>router>WAN>LAN ...

Not really sure what you are asking?
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