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NAT Puzzle

I have been asked if it is possible to do something unusual with a range of IP Addresses.

The request is for a range of addresses that, when used as destinations, all end up using a single IP as a destination. Sort of a backwards NAT.

So if I send a request to 10.1.10.1 - 10.1.10.20 all of the requests end up getting sent to 192.168.10.10.

I can set up an overload where the 10.1 "source" addresses all appear as the 192 address. But if the very first packet is sent to 10.1.10.20 from node 10.1.10.250 I don't think that the "destination" will be translated to 192.168.10.10.

I have a router and a pix. Any possibilities?

Why would anyone want to do this? They want to stress test a server initiating traffic to 250 nodes but they only have one "receiver" node to test with (and it can only listen on one interface/IP). Thus they want to enter a list of 250 addresses into the server but have them all actually arrive at the receiver node with a single destination IP.

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New Member

Re: NAT Puzzle

Hi there,

In PIX 6.3 the manual say that you can't do this. In common sense you can try this (I don't have pix to try it but I don't think will work):

static (inside,outside) 10.1.10.1 192.168.10.10 netmask 255.255.255.255

static (inside,outside) 10.1.10.2 192.168.10.10 netmask 255.255.255.255

static (inside,outside) 10.1.10.3 192.168.10.10 netmask 255.255.255.255

......

......

static (inside,outside) 10.1.10.18 192.168.10.10 netmask 255.255.255.255

static (inside,outside) 10.1.10.19 192.168.10.10 netmask 255.255.255.255

static (inside,outside) 10.1.10.20 192.168.10.10 netmask 255.255.255.255

The manual say this:

"... Because you cannot use the same local address in static NAT or static PAT commands, the order of static commands does not matter...."

Emilio

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