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Sumanta_88744's avatar
Sumanta_88744
Icon for Cirrus rankCirrus
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_
Icon for Nacreous rankNacreous

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
Icon for Cirrus rankCirrus
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.