RE: IP Spoofing/Masquarading



I suggest you read the RFC:

" and packets with private source or destination addresses
should not be forwarded across such links. Routers in networks not
using private address space, especially those of Internet service
providers, are expected to be configured to reject (filter out)
routing information about private networks. If such a router receives
such information the rejection shall not be treated as a routing
protocol error."

Should not be forwarded != cannot be forwarded.

Remember that the same gear that is used by an ISP is used by
Enterprises. Routers, firewalls, etc, need to be able to route the
private address space IPs as there is always a business reason to do so.

Thanks,
Erik

-----Original Message-----
From: listbounce@xxxxxxxxxxxxxxxxx [mailto:listbounce@xxxxxxxxxxxxxxxxx]
On Behalf Of aditya mukadam
Sent: Wednesday, September 09, 2009 5:04 AM
To: M.D.Mufambisi; pen-test@xxxxxxxxxxxxxxxxx; security-basics
Subject: Re: IP Spoofing/Masquarading

Private IPs (as per RFS 1918) cannot be routed over internet.

Thanks,
Aditya Govind Mukadam


On Wed, Sep 9, 2009 at 11:49 AM, M.D.Mufambisi <mufambisi@xxxxxxxxx>
wrote:

I understand that IP packets can be spoofed ie change the source
address to make it look like they originated from the internal LAN.
However, when this is done across the internet, with a private IP
address in its source field, how does this packet get routed through
the internet?

Kind Regards


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