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Sumanta_88744's avatar
Sumanta_88744
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Jun 09, 2016

Persistence profile - How will I use source address affinity based load balancing?

Hi Experts How will I use source address affinity based persistence profile across different pools having different IP but same port? For example there are two virtual server 1.1.1.1:80 and 2.2.2.2...
application delivery
BIG-IP
LTM
  • Yann_Desmarest_'s avatar
    Yann_Desmarest_
    Jun 11, 2016

    Don't worry, it's a common scenario for me.

    Just pay attention that the upstream proxy insert the "X-Forwarded-For" header, or maybe another one "True-Client-IP" or even "X-Client-IP".

    If you are just nating using a firewall, I think that the header is not inserted.

    I add this peace of code in the example :

     

    set clientip [IP::client_addr]

     

    because you may have situation where there is no "X-Forwarded-For" in the request, so that we can persist also in this scenario.

Yann_Desmarest's avatar
Yann_Desmarest
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Jun 11, 2016

Yes that's possible. Below an example that you may need to adapt to fit your needs :

 

when HTTP_RESPONSE {
    persist add uie $clientip
}
when HTTP_REQUEST {
    set clientip ""
    if { [HTTP::header exists "X-Forwarded-For"] } {
        set clientip [HTTP::header "X-Forwarded-For"]
    } else {
        set clientip [IP::client_addr]
    }
    persist uie $clientip
}

 

  • Sumanta_88744's avatar
    Sumanta_88744
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    Jun 11, 2016
    Hi Yann Thanks for your help on this. Please note that in my case, client IP in incoming session traffic to F5, represents a single IP NAT-ed to different source IPs. For example, different PCs using DHCP enabled IP addresses behind a firewall, but with single public IP, from the firewall. So, the IP header has single IP, but the http XFF header will have different client IPs. Will this at all work? I haven't come across such a complex scenario before.