iRule to randomly change source IP

And maybe you find these useful as well:

when CLIENT_ACCEPTED {     
    snat 10.10.10.[expr ( [getfield [IP::client_addr] "." 4] % 32 ) + 1]
   snat 10.10.[getfield [IP::client_addr] "." 3].[getfield [IP::client_addr] "." 4]
}

The following one simulates varying clients by inserting a randomized X-Forwarded-For and uses another internal virtual server for processing:

when HTTP_REQUEST {
    snat automap
    HTTP::header insert X-Forwarded-For [expr int(rand()*128) + 32].[expr int(rand()*254)].[expr int(rand()*254)].[expr int(rand()*254)]    
    virtual vs_internal
}

Hi Piotr,

when CLIENT_ACCEPTED {
    snat [expr { int(rand()*193) + 1}].[expr { int(rand()*254) + 1}].[expr { int(rand()*254) +1}].[expr { int(rand()*253) +1}]
}

Thanks, Stephan

I'm trying to do this random_ip_irule (device) but won't works. With 2 VS and iRules. Could you tell me if had some changes to 13.1.0.2?

Hi Pitor,
I understand that you had a question back in 2015 about simulating clients from different geolocations using a limited pool of private IP addresses. Although your question was from a few years ago, I wanted to provide an updated answer for anyone facing a similar challenge in 2023.

If you're looking to simulate clients from different geolocations using a limited pool of private IP addresses, you can consider using a random IP address generator. I recommend checking out https://randomtools.io/random-ipaddress-generator/ for a ready-to-use tool that can generate country-located IP addresses.

To achieve the desired flow:

1. When a packet arrives with a private IP, you can use the random IP generator from the provided link to generate a new IP address representing a different geolocation.
2. Replace the original private IP with the generated IP before forwarding the request to the server.
3. If possible, consider modifying the response packet's destination IP back to the original source IP before sending it back to the client.

Please keep in mind that modifying IP addresses in transit may have specific limitations or dependencies on the network infrastructure and client capabilities.