amenite
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join:2002-11-21
Ridgewood, NJ
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| reply to pvale
Re: Rolling my own
said by pvale  :
What if you are running 2 NAT devices in series? I'm running a Freesco PC-made-into-router, feeding a Netgear RT314, and my machines are connected behind the Netgear box. I haven't read the mentioned paper, but the only ID that would show on the WAN side of the Freesco would be the Netgear's. Since Freesco is built on a small Linux distribution, I'm sure I can change what it does/reports.
The ID in question is the IP id string assigned to each packet by the OS, not the IP address of the NAT device. It only has to do with the IP address in that you would be monitoring/analyzing the all packet headers originating from a particular IP address.
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Time is an abstract concept invented by carbon based life forms to monitor their constant decay.-Thunderclese |
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AthlGrond
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join:2002-04-25
Aurora, CO
 ·Comcast
| said by amenite :
The ID in question is the IP id string assigned to each packet by the OS, not the IP address of the NAT device.
Are the IPid's not assigned by the NAT device? Seems like they would have to be. (so the NAT device could send the packets to the correct IP in the LAN) |
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amenite
The Soylent - It's People
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join:2002-11-21
Ridgewood, NJ
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·Verizon Online DSL
| said by AthlGrond :
said by amenite :
The ID in question is the IP id string assigned to each packet by the OS, not the IP address of the NAT device.
Are the IPid's not assigned by the NAT device? Seems like they would have to be. (so the NAT device could send the packets to the correct IP in the LAN)
According to the article, the "IP id" field is generated by the host, and is only used to reassemble fragmented packets. It must be unique among all packets of one protocol that have the same source and destination address (to allow for correct reassembly in case of fragmentation). I am assuming that the NAT device only alters the source IP, or leaves enough of the IP id string intact to allow the technique to work.
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Time is an abstract concept invented by carbon based life forms to monitor their constant decay.-Thunderclese |
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AthlGrond
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join:2002-04-25
Aurora, CO | Thanks, I reread it and much clearer now. You are correct. |
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